Biology Commons^™

Unstable And Stable Classifications Of Scombroid Fishes, Kent E. Carpenter, Bruce B. Collette, Joseph L. Russo

Biological Sciences Faculty Publications

Many cladists believe that a classification should strictly reflect a cladistic hypothesis. Consequently, they propose classifications that often differ markedly from existing ones and are potentially unstable due to phylogenetic uncertainty. This is problematic for economically or ecologically important organisms since changing classifications can cause confusion in their management as resources. The classification of the 44 genera of scombroid fishes (the mackerels, tunas, billfishes, and their relatives) illustrates this problem of instability. Previous cladistic analyses and analyses presented in this paper, using different data sets, result in many different cladistic hypotheses. In addition, the inferred cladograms are unstable because of …

Signal And Image Manipulation In Microanalysis, P. W. Hawkes

Scanning Microscopy

Scanning electron microscopes, and transmission instruments equipped for EELS, generate a host of signals and hence of images from each pixel of the specimen. Numerous ingenious ways of coping with this multiplicity of information, which may be very different in character, have been devised, but no detailed study has yet been made of the appropriate mathematical structure, with the aid of which all this information could be manipulated reasonably easily.

One such structure falls within the subject that has come to be known as Image Algebra, the principal attraction of which is that we deal directly with entire images …

Degeneration And Reorganization Of Vestibular Epithelia After Local Aminoglycoside Application In The Mammalian Inner Ear, J. Dupont, A. Guilhaume, J. -M. Aran

Scanning Microscopy

The development of degeneration of vestibular end organs and their possible reorganization have been observed over a 2 year period after local application of sisomicin in the inner ear using scanning electron microscopy (SEM). Degeneration of stereocilia took place as early as 5 days after the treatment in the utricule, the saccule and the cristae. At 10 days, almost the entire surface of these sensory epithelia presented a smooth aspect without specific structure. However, after 15 days, an epithelial reorganization developed with clear limits between cells. At 25 days, systematic kinociliary structures were observed at the apical surface of the …

An Integrated Study Of The Morphological And Gross-Elemental Consequences Of Methyl Mercury Intoxication In Rats, With Particular Attention On The Cerebellum, K. Leyshon, A. J. Morgan

Scanning Microscopy

Methylmercury accumulates in the kidney and liver of rats, but fairly selectively damages the cerebellum, resulting in the clinical symptoms of neurological ataxia after prolonged exposures. Within the cerebellum, morphological examination indicated that the small granule cells beneath the Purkinje layer are especially susceptible to the toxin, showing signs of pyknosis during the phase of locomotory disability, whilst the large Purkinje cells are relatively resistant to cytotoxic injury. Flame photometric and electron probe X-ray microanalysis (EPXMA) of digested samples of the major organs failed to detect any significant changes in the Na, K, Ca, Mg, S and P concentrations of …

Effects Of Modulated And Continuous Microwave Irradiation On The Morphology And Cell Surface Negative Charge Of 3t3 Fibroblasts, Z. Somosy, G. Thuróczy, T. Kubasova, J. Kovács, L. D. Szabó

Scanning Microscopy

Mouse embryo 3T3 cells were irradiated with 2450 MHz continuous and low frequency (16 Hz) square modulated waves of absorbed energy ranging from 0.0024 to 2.4 mW/g. The low frequency modulated microwave irradiation yielded more morphological cell changes than did the continuous microwave fields of the same intensity. The amount of free negative charges (cationized ferritin binding) on cell surfaces decreased following irradiation by modulated waves but remained unchanged under the effect of a continuous field of the same dose. Modulated waves of 0.024 mW/g dose increased the ruffling activity of the cells, and caused ultrastructural alteration in the cytoplasm. …

Heterogeneity Of Crystals Attached To The Human Enamel And Cementum Surfaces After Calculus Removal In Vitro, T. Kodaka, K. Debari, M. Yamada

Scanning Microscopy

Twenty one extracted human teeth with dental calculi on the enamel and cementum surfaces, fixed in 10% neutral formaldehyde, were selected for this study. After ethanol dehydration and air drying, these calculi were removed by tweezers to observe the teeth surfaces under them. The inspection of these surfaces using SEM and EDX revealed hexahedrally based crystals including pseudocuboidal, rhombohedral and variable rugged rocky shapes. These crystals were identified as Mg-containing whitlockite. The pseudocuboidal crystals, measuring about 4.5 μmin maximum length, were widely distributed on the cervical enamel surface previously covered by calculus. On the root surface, however, these areas decreased …

A Scanning Electron Microscopic Morphological And Semi-Quantitative Evaluation Of Rat Stomach Treated With Colloidal Bismuth Subcitrate And Alcohol, C. Winters, S. M. Hinsull, Z. Gregory

Scanning Microscopy

Scanning electron microscopy was utilised to study the effect of absolute alcohol on the normal morphology of the rat stomach, together with the gastroprotective actions of colloidal bismuth subcitrate. Studies on normal gastric morphology revealed that the major portion of the stomach was covered by a protective coating of mucus. However, there was considerable variation in the integrity of the mucosal surface of the control animals, with the loss of surface epithelial cells in some regions which may account for the variation in response to necrotising agents. The long-term administration of the gastrocytoprotective agent colloidal bismuth subcitrate resulted in a …

Effects Of Low Energy Beta-Irradiation From Tritiated Water On The Morphology Of 3t3 Fibroblasts, Z. Somosy, Tamara Kubasova, J. Kovács, G. J. Köteles

Scanning Microscopy

Cellular alterations of cultured 3T3 cells irradiated with beta-rays from tritiated water were studied by scanning and transmission electron microscopy. We observed decreased negative surface charges, vacuolization of rough endoplasmic reticulum and Golgi-complex, degeneration of mitochondria, increase of lysosomal activity and changes in distribution and amount of microfilaments in the irradiated cells, that parallelled changes in cell shape.

Decreased Sprint Speed As A Cost Of Reproduction In The Lizard Scelopours Occidentalis: Variation Among Populations, Barry Sinervo, Richard Hedges, Stephen C. Adolph

All HMC Faculty Publications and Research

Decreased mobility of gravid females is thought to be an important cost of reproduction in lizards. We measured sprint speeds of female western fence lizards (Sceloporus occidentalis Baird and Girard) before and after they had oviposited. Females from two California populations were about 20% slower when gravid, females from an Oregon population were about 30% slower, and females from a Washington population were about 45% slower, compared to their speeds after recovering from reproduction. The decrease in sprint speed persisted for several weeks after oviposition, suggesting that reproduction impairs sprint performance by affecting body condition in addition to the burdening …

Diapause In The Earthworm, Aporrectodea Longa: Morphological And Quantitative X-Ray Microanalysis Of Cryosectioned Chloragogenous Tissue, A. J. Morgan, C. Winters

Scanning Microscopy

The earthworm, Aporrectodea longa, which experiences an apparent obligatory physiological resting state (“diapause”) in the temperate Summer, was collected monthly from February through to October. Morphological examination of the chloragocytes, and quantitative electron probe X-ray microanalysis of their constituent chloragosome granules prepared by cryoultramicrotomy and air-dried/smearing, were undertaken over this period. Worms entered diapause in May, and emerged from it between August and September. The long-term energy stores in the form of lipid, in addition to the more usual polysaccharide (glycogen) reserves, were accumulated by early diapause; the lipid was gradually consumed during diapause. In addition, the structure and composition …

A Scanning Electron Microscopic Study Of The Morphology Of Scyphidia Physarum Lachmann, 1856 (Ciliophora: Peritrichida), A. Warren

Scanning Microscopy

The morphology of Scyphidia physarum was investigated by scanning electron microscopy (SEM). Both contracted and uncontracted zooids were examined. The pellicular striations encircled the body at mean intervals of 1.1 µm. Pores were randomly distributed over the body surface with a mean density of 21 pores per 100 µm 2. The telotroch band was represented by three closely spaced striations. The adoral ciliature consisted of a single row of cilia in the haplokinety and three rows in the polykinety. The two sets of cilia were separated by a pellicular ridge. At the end of each row of cilia was a …

Ultrastructural Investigations Of The Bone And Fibrous Connective Tissue Interface With Endosteal Dental Implants, David E. Steflik, Ralph V. Mckinney, Allen L. Sisk, David L. Koth, Baldev B. Singh, Gregory R. Parr

Scanning Microscopy

The interface between the tissues of the oral cavity and ceramic and titanium cylindrical endosteal dental implants was investigated with correlated light microscopy, transmission electron microscopy and scanning electron microscopy. This study suggested that mandibular bone can directly interface and form an intimate association with one-stage endosteal dental implants. This potential attachment matrix is composed of a composite of calcified bone, and an osteoid unmineralized matrix in association with an apparent osteogenic connective tissue. Further, results from this study suggested that at a level inferior to the junctional epithelium, and superior to the level of crestal bone, fibrous connective tissue …

Description Of The Tadpoles Of Gastrophryne Pictiventris And Nelsonophryne Aterrima (Anura: Microhylidae), With A Review Of Morphological Variation In Free-Swimming Microhylid Larvae, Maureen A. Donnelly, Rafael O. De Sá, Craig Guyer

Biology Faculty Publications

The tadpoles of Gastrophryne pictiventris and Nelsonophryne aterrima are described based on material collected in Costa Rica and Panama, respectively. The tadpole of G. pictiventris resembles those of the other species of Gastrophryne. The tadpole of N. aterrima differs from other New World microhylid tadpoles in location of the vent tube (medial), the spiracular opening (ventral to the gut), and eyes (dorsolateral). The unique configuration of mouthparts in N. aterrima is described. Morphological variation in microhylid tadpoles is reviewed and six larval characters are analyzed cladistically for IO New World microhylid genera.

Quantitative Evaluation Of Scanning Electron Microscopy-Examined Ciliary Morphological Changes In Control And Noise Exposed Guinea Pig Cochleas, S. Rydmarker, P. Nilsson, D. E. Dunn, C. Lindqvist

Scanning Microscopy

Many investigations of noise-induced hearing loss have demonstrated a poor correlation between hearing threshold and hair cell loss. One reason for this is that more subtle changes in the hair cell, such as detailed morphological changes of stereocilia, have not been evaluated. However, examining such changes increases the problem of distinguishing experimental pathological changes from artefacts. Preparation of the specimen for scanning electron microscopy (SEM) may result in too many artefacts for an adequate quantification of defects due to noise exposure.

One problem with some earlier studies seems to be lack of controls and/or statistical analysis for the purpose of …

Morphology And Chemical Composition Of Dental Calculi Mainly Composed Of Whitlockite, Toshiro Sakae, Hirotsugu Yamamoto, Hiroyuki Mishima, Takashi Matsumoto, Yukishige Kozawa

Scanning Microscopy

The morphology and chemical composition of two subgingival calculus samples, which were composed of magnesium-whitlockite with a Mg/Ca molar ratio of approximately 0.1 as shown by X-ray powder diffraction, were analyzed semiquantitatively using energy-dispersive spectroscopy (EDS) combined with scanning electron microscopy (SEM). The Ca/P molar ratio values for 33 EDS-analyzed materials ranged from 1.24 to 2.03 with an average of 1.49, and the (Mg+Ca)/P molar ratio values ranged from 1.43 to 2.28 with an average of 1.63. The average Mg/Ca molar ratio was 0.10, a value very close to that obtained by X-ray diffraction analysis.

The EDS-analyzed materials were grouped …

Megakaryocyte Motility And Platelet Formation, Robert M. Leven

Scanning Microscopy

The mechanism of platelet formation is reviewed with special emphasis on the role of the cytoskeleton. The three major theories for platelet formation are by cytoplasmic budding, cytoplasmic dissolution or pseudopod formation. Most evidence indicates that platelets form as fragments of megakaryocyte pseudopodia. Pseudopodia formation is stimulated in vitro by thrombocytopenic rabbit plasma. It is inhibited by vincristine and altered by taxol. Cytochalasins cause pseudopodia to form in isolated megakaryocytes. Therefore, normal pseudopodia formation may depend on a combination of microfilament disorganization and microtubule elongation.

The Study Of Biominerals By High Resolution Transmission Electron Microscopy, Stephen Mann

Scanning Electron Microscopy

This paper presents an overview of the study of the ultrastructure of biogenic inorganic solids (biominerals) using high resolution transmission electron microscopy (HRTEM). A range of biominerals have been studied including iron oxides, calcium phosphates, calcium carbonates and silica. The studies have revealed information concerning the structural complexity of these materials and have identified crystallographic order and disorder at the nanometre level. In addition, the results have aided the elucidation of the mechanisms of nucleation and growth of biogenic minerals.

The Morphology Of Thin Metal Coatings Formed By Rotary Shadowing Biological Species In High Vacuum, J. A. Panitz

Scanning Electron Microscopy

Rotary Shadowing has been used to increase the image contrast of biological species observed during edge-projection imaging in the transmission electron microscope. In this imaging mode, biological species are adsorbed from aqueous solutions onto a highly curved substrate and viewed, over its edge, in a direction parallel to its surface. Since the substrate is not placed between a biological adsorbate and the photographic emulsion that records its image, any material can be used as a support (including high-Z metals and semiconductors). Binding to these technologically interesting materials is observed with unusual clarity and contrast, even at 200kV. Individual adsorbates and …

Estructura Del Ovario De Chthonerpeton Indistinctum (Reinhardt Y Lutken, 1862) (Amphibia: Gymnophiona) Durante La Gestación, Rafael O. De Sá, Nibia Berois

Biology Faculty Publications

La morfología e histología del ovario para varias especies del orden Gymnophiona ha sido reportada por Wake (1968, J. Morphol. 126, 291) y para C. indistinctum por los autores (1984, XXIV Reunión de Comunicaciones, Soc. Zool. Uruguay).

Continuando con los estudios sobre el aparato genital de esta especie vivípara, se presenta ahora la estructura del ovario durante la gestación.

Se procesaron con fines histológicos, ovarios de dos hembras grávidas colectadas en las costas de los Dep. Montevideo y San José en abril, 1983. El número de ejemplares trabajados es muy reducido dado lo difícil que resulta su colecta …

The Fern Prothallium As An Experimental Object For Morphogenetic Studies, Dorothy Anita Douglas

Theses & Honors Papers

No abstract provided.

Present Day Concepts Of The Gene With Special Reference To The Salivary Chromosome Of Drosophila Melanogaster, Lola S. Reed

Biology Honors Papers

This 14 page thesis discusses the nature and function of the gene, including experimental work, chromosome banding, chromosome maps and methods of determination of gene loci.