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Heterochromatin Protein 1, A Known Suppressor Of Position-Effect Variegation, Is Highly Conserved In Drosophila, Robert F. Clark, Sarah C.R. Elgin

Biology Faculty Research

The Su(var)205 gene of Drosophila melanogaster encodes heterochromatin protein 1 (HP1), a protein located preferentially within beta-heterochromatin. Mutation of this gene has been associated with dominant suppression of position-effect variegation. We have cloned and sequenced the gene encoding HP1 from Drosophila virilis, a distantly related species. Comparison of the predicted amino acid sequence with Drosophila melanogaster HP1 shows two regions of strong homology, one near the N-terminus (57/61 amino acids identical) and the other near the C-terminus (62/68 amino acids identical) of the protein. Little homology is seen in the 5' and 3' untranslated portions of the gene, as well …

Southern Nevada Effluent Wetlands: A Proposed Cooperative Venture Between The Bureau Of Reclamation & City Of Las Vegas, Bureau Of Reclamation

Publications (WR)

Throughout North America there is a growing interest in constructed wetlands, both as relatively inexpensive, low-maintenance systems for removing nutrients from wastewater, and as a means of using municipal wastewater to enhance wildlife habitat and create public use opportunities. Because wetlands appear to have good potential as a component in the overall management of scarce water resources, the Bureau of Reclamation (Reclamation) has undertaken several cooperative research and demonstration projects to evaluate their effectiveness in a variety of local environments. While a number of projects have demonstrated that wetlands can be beneficially employed to improve water quality, few such projects …

Evaluation And Management Of Dietary Habits In Japanese Renal Stone Formers, Haruo Ito, Tadashi Kotake, Naoto Miura

Scanning Microscopy

To elucidate the relationship between the formation of kidney stones and diet, we carried out a dietary investigation in patients with urinary tract stones. Dietary intakes were estimated for 36 patients (24 men, 12 women) with calcium stones, and compared with the official dietary requirements for the Japanese.

Total protein intake, animal protein intake and animal protein ratio were significantly higher for patients with stones in both men and women. Dietary salt intake was significantly higher for male patients and the total group. Dietary calcium and carbohydrate intakes were significantly lower for patients with stones in men and the total …

Ultrastructural Effects Of Therapeutic Irradiation On Human Epithelial Tumors, P. Kellokumpu-Lehtinen

Scanning Microscopy

Irradiation induces several cellular changes leading to death of cancer cells and normal cells which is followed by repairing processes of normal cells. We have studied the effects of therapeutic irradiation on head and neck cancers. Tissue samples taken before and during the radical irradiation (50-80 Gy) of the squamous cell carcinomas of the head and neck region were examined by light and electron microscopy. Nuclear atypia was most pronounced cellular change during irradiation. The tumor invasion pattern remained unchanged but the number of mitoses decreased. Lymphocytic infiltration increased at the beginning of the therapy (from 10 to 30 Gy) …

Importance Of Mild Hyperoxaluria In The Pathogenesis Of Urolithiasis - New Evidence From Studies In The Arabian Peninsula, W. G. Robertson, H. Hughes

Scanning Microscopy

The hypothesis that mild hyperoxaluria is more important than hypercalciuria in the pathogenesis of urolithiasis is re-examined in the light of new evidence. Small increments in urinary oxalate in the normal to high-normal range are much more critical than similar rises in urinary calcium for increasing the relative supersaturation of urine with respect to calcium oxalate, the oxalate/calcium ratio in urine, the total volume of calcium oxalate crystals excreted, the proportion of abnormally large crystals and aggregates of calcium oxalate and the severity of the disorder as defined by the recurrence rate of stone-formation. Data from the Arabian Peninsula, where …

Effect Of Chronic Treatment With Diuretics On Mouse Liver: A Morphological And Microanalytical Investigation, Ann-Christin Mork, Anne Von Euler, Godfried M. Roomans

Scanning Microscopy

In an attempt to produce an animal model for the disease cystic fibrosis (CF), mice were treated chronically with the diuretics amiloride and furosemide, in order to cause chronic inhibition of transepithelial ion transport. Experiments were carried out on adult mice (2 months treatment); in addition, pregnant mice were treated with diuretics, and tissue from offspring 2 and 7 days post partum was investigated. Since biliary cirrhosis is a common occurrence in CF, hepatocytes in the treated mice were investigated by X-ray microanalysis and by light and electron microscopy.

Treatment with amiloride caused a significant decrease in cellular Na concentration …

Dentinogenesis And The Calciotraumatic Response To The Injection Of Lead Or Fluoride Ions, John Appleton

Scanning Microscopy

A number of ions can disturb the formation of dentine resulting in a calciotraumatic response. The calciotraumatic response following the injection of sodium fluoride was investigated using backscattered electron imaging in the scanning electron microscope and compared with the response to lead acetate. With fluoride, there was formation of a hypermineralized band succeeded by a relatively hypomineralized band, but with lead acetate, only a hypomineralized band was produced. However, there were some differences in the response between the labial and lingual dentine with both ions. In the labial dentine following injection of sodium fluoride, the onset of hypermineralization was less …

Scanning Electron Microscope Observations Of Brine Shrimp Larvae From Space Shuttle Experiments, Lynnette Debell, Avelina Paulsen, Brian Spooner

Scanning Microscopy

Brine shrimp are encysted as gastrula stage embryos, and may remain dehydrated and encysted for years without compromising their viability. This aspect of brine shrimp biology is desirable for studying development of animals during space shuttle flight, as cysts placed aboard a spacecraft may be rehydrated at the convenience of an astronaut, guaranteeing that subsequent brine shrimp development occurs only on orbit and not on the pad during launch delays.

Brine shrimp cysts placed in 5 ml syringes were rehydrated with salt water and hatched during a 9 day space shuttle mission. Subsequent larvae developed to the 8th larval stage …

Microvasculature Of Normal And Hydropic Labyrinth, Yoshiaki Nakai, Haruhiko Masutani, Makoto Moriguchi, Kazuhiro Matsunaga, Akihumi Kato, Hitoshi Maeda

Scanning Microscopy

The microvasculature of the inner ear in guinea pigs and humans was observed with a scanning electron microscope using corrosion casting method. Alterations in the inner ear vasculature which occurred in association with experimental endolymphatic hydrops were also investigated. The results thus obtained are summarized as follows:

1. In the cochlea and vestibule, the arteries, coiled arterioles, and the veins are endowed with their respective characteristic morphologic features and play a role in the regulatory mechanisms of circulation.

2. The point in humans which is most different from guinea pigs was that coiled arterioles in the cochlea and the coil-like …

Cochlear And Vestibular Epithelia From A Patient With Meniere's Disease: A Case Study, K. C. Horner

Scanning Microscopy

Scanning electron microscopy observations were carried out on the cochlear and vestibular epithelia of the left temporal bone of a Meniere' s patient. There was almost complete absence of hair cells in the basal turn of the cochlea. The outer hair cells of the second turn presented an abnormal shortening of the shorter stereocilia within a tuft, reminiscent of the specific atrophy of the short and middle stereocilia in the ciliary tufts of outer hair cells in the guinea pig with experimental hydrops. The cilia of the inner hair cells showed fusion and giant cilia formation. Hair cells were observed …

The Splenic Microvasculature Of The Red-Eared Turtle (Chrysemys Scripta Elegans): A Study Concerning The Question Whether The Circulation Is Anatomically Open Or Closed, R. Blumer, H. Ditrich, H. Splechtna

Scanning Microscopy

The splenic microvasculature of the turtle Chrysemys scripta elegans was studied by means of scanning electron microscopy of vascular corrosion casts and critical point dried tissue. In addition light- and transmission electron microscopic investigations were carried out. Within the organ the arteries are surrounded by periarterial lymphoid sheaths. The majority of the arterial capillaries, which emerge from these central arteries have open endings within the reticular meshwork of the red pulp. Approximately 10% of the capillaries directly connect with the venous origins. Since these venous capillaries of C. scripta elegans resemble those of nonsinusal mammalian spleens we termed them pulp …

Response Of The Esophageal Epithelium To Concomitant Cis-Dichlorodiammineplatinum(Ii) And Radiation Treatment. An Electron Microscopic Study In Rabbits, M. Albertsson, M. Cwikiel, C. H. Håkansson, M. Palmegren

Scanning Microscopy

The rabbit esophageal mucosa was irradiated with daily fractions of 2 Gy up to an accumulated dose of 20 Gy (total dose 2, 6, 10. 16 or 20 Gy). Fifteen to forty-five minutes before the start of each irradiation 0.3 mg Cis-dichlorodiammineplatinum (cis-DDP, cisplatinum) was given by intraperitoneal injection to each rabbit. Examinations were carried out 1-10 days after each fractionation schedule, when specimens were taken for morphological investigations.

Scanning electron microscope (SEM) examination showed a gradual development of damage with cell loss and structural disarrangement of the microridges and whorls on the surface. However, with further treatment the esophageal …

Ecological Evaluation Of Proposed Dredged Material From Richmond Harbor, M. R. Pinza, J. A. Ward, H. L. Mayhew, J. Q. Word, Dev Niyogi, N. P. Kohn

Biological Sciences Faculty Research & Creative Works

During the summer of 1991, Battelle/Marine Sciences Laboratory (MSL) was contracted to conduct sampling and testing of sediments proposed for dredging of Richmond Harbor, California. The MSL collected sediment cores to a depth of [minus]40 ft MLLW ([minus]38 ft + 2 ft over depth) from 28 (12-in. core) and 30 (4-in. core) stations. The sediment cores were allocated to six composite samples referred to as sediment treatments, which were then subjected to physical, chemical, toxicological, and bioaccumulation testing. Physical and chemical parameters included grain size, total organic carbon (TOC), total volatile solids (TVS), oil and grease, total petroleum hydrocarbons (TPH), …

The Cockburn Sound Fishery Management Plan. Summary Of Submission And Final Recommendations For Management., A. Millington

Fisheries Management Papers

Identifiable "unit" fisheries in Cockburn Sound are: Beach bait fishing netting Fish set netting Crab netting Mussel diving Line fishing and pot fishing This report recommends measures for the longer term management of these fisheries In particular, that they be managed as limited entry fisheries under Section 32 of the Fisheries Act 1905. Strict entry criteria are proposed for continued access to these fisheries. Rules are proposed for boat replacement. Licence transferability is considered in detail. No decisions to be made on the policy for licence transfers until the final number of participants in each fishery is determined. Owner operation, …

Avian Forelimb Muscles And Nonsteady Flight: Can Birds Fly Without Using The Muscles In Their Wings?, Kenneth P. Dial

Biological Sciences Faculty Publications

Intensity patterns of electromyographic (EMG) signals from selected muscles of the wing were studied during different modes of flight in trained Rock doves (Columba livia). Shoulder muscles exhibited a stereotypic pattern producing maximal EMG intensity during the deceleration phases of the upstroke and the downstroke, whereas the muscles of the brachium and antebrachium acted primarily as joint stabilizers during level flapping flight. During nonsteady flight (e.g. takeoff, landing, vertical ascending flight), the distal forelimb muscles exhibited maximal EMG intensity; their primary function appears to be associated with changing the camber and planform of the wing during rapid oscillation. During steady …

The Drosophila Period Gene And Dye Coupling In Larval Salivary Glands: A Re-Evaluation, Kathleen King Siwicki, K. K. Flint, J. C. Hall, M. Rosbash, D. C. Spray

Biology Faculty Works

No abstract provided.

Retention Of Cellular Viability And Growth Potential In Cryopreserved Bovine Arterial Tissue: Implications For Clinical Use Of Cryopreserved Vascular Allografts, Kip G. Gardner

Biological Sciences Theses & Dissertations

Segments of bovine calf aortas and pulmonary arteries were cryopreserved at -196° C for two weeks to 18 months and subsequently thawed. Cellular morphology, viability, and growth potential in these segments were then compared with the same attributes in segments from fresh (control) arteries. Scanning electron microscopy revealed no disruption of intimal surfaces attributable to cryopreservation. Endothelial cells were successfully cultured from all cryopreserved arterial segments. Endothelial monolayers grown from cryopreserved arteries had a cobblestone appearance and expressed Factor VIII antigen but not smooth muscle alpha-actin. Plating efficiency in primary cultures of endothelial cells was lower for cryopreserved arteries than …

The Effect Of Varying Environmental Conditions On Phytolith Morphometries In Two Species Of Grass (Bouteloua Curtipendula And Panicum Virgatum), T. B. Ball, J. D. Brotherson

Scanning Microscopy

Solid deposits of SiO₂ (phytoliths) accumulate in many plants in specific intracellular and extracellular locations. Phytoliths have morphological characteristics unique to some taxa and therefore have taxonomic significance. Phytoliths persist and maintain their morphological integrity long after a plant has died, thus becoming a microfossil of the plant that produced them. Development of phytolith sytematics for microfossil phytoliths has traditionally followed a typological approach based on simple verbal descriptions of shape. A new method for use in phytolith sytematics is the morphometric approach which employs computer-based Image Analysis Systems to make quantified measurements of morphological parameters (size, shape, texture, …

Scanning Electron Microscopy Of Nerve Fibers In The Dog Cochlea, Hirofumi Morita, Tomoyuki Hoshino, Kunihiro Mizuta

Scanning Microscopy

The nerve fiber arrangement inside the organ of Corti in the dog was studied. Thick sections were cut serially from celloidin-embedded cochleas and observed with a scanning electron microscope (SEM). The nerve fibers in the organ of Corti were clearly exposed in sections cut in the horizontal plane. The arrangement of nerve fibers in the dog showed considerable difference from that of other species. The tunnel basilar fibers in the dog curved basalward, and took a long longitudinal course to form a broad bundle in the center of the tunnel floor. This bundle has not been found in adult animals …

Microwear Studies Of Early African Hominid Teeth, Pierre-François Puech

Scanning Microscopy

Studies of microwear on fossil hominid teeth have become an important approach in paleoanthropology. Since there are very few samples of early hominids from East Africa with suitable teeth, this paper presents a review of the occurrence of some dental wear characteristics to provide a data base for reconstructing the diet of the early hominids.

Distinctive microwear features such as furrows, crenulations, stress lines and deep grooves, are interpretive tools that can be used in a biomechanical approach. Occurrence of the same dental microwear patterns in extant species with known dietary differences is indicative of foods that have probably been …

Comparison Of Cryopreparation Techniques For Electron Probe Microanalysis Of Cells As Exemplified By Human Erythrocytes, Karl Zierold

Scanning Microscopy

Erythrocytes in human blood were used to evaluate the reliability of cryopreparation techniques for electron probe X-ray microanalysis of biological cells and tissues. The elemental content determined by X-ray microanalysis of ultrathin freeze-dried cryosections was found to be consistent with data known from the literature. Considerable redistribution of the intracellular elemental composition was found after freeze-substitution as well as after freeze-drying followed by resin embedding. Two conclusions are drawn from this study: 1. Erythrocytes in human blood are a suitable reference specimen for evaluation of specimen preparation techniques for microanalysis. 2. At present, freeze-dried cryosections are the most reliable specimen …

Information And Misinformation Regarding Ischemia Of Heart Muscle Tissue. The Cause Of Cell Death During Blood Reperfusion And Reactivation Of Heart Muscle Tissue After Prolonged Ischemia, Fritiof S. Sjöstrand

Scanning Microscopy

An electron microscopic study of heart muscle tissue exposed to six hours ischemia and prepared according to the low denaturation embedding technique revealed a structural modification confined to the mitochondrial cristae. The modification consisted of a removal of Krebs cycle enzymes from the cristae. Reperfusion of the ischemic tissue after four hours ischemia led to extensive breakdown of the mitochondrial structure and contractility could not be restored. However, when after six hours ischemia the ischemic tissue was reperfused with blood, the composition of which had been modified to stimulate mitochondrial function, no additional structural changes were observed and contractility was …

Morphological Study Of Gastric Lesions Developing In The Rat Under Several Damaging Conditions: Modifications Induced By Pretreatment With Zinc Acexamate, M. Luisa Bravo, Ginés Escolar, Carmen Navarro, Ramón Fontarnau, Oriol Bulbena

Scanning Microscopy

Lesions developing in the gastric mucosa of the rat after exposure to different gastric damaging agents (100 mg/kg aspirin, and 70% or 100% ethanol) were assessed by scanning electron microscopy. The severity of the lesions was quantified according to morphological criteria. Modifications in the severity of these lesions induced by pretreatment with zinc acexamate were also analyzed. The scanning electron microscope revealed that with the exception of absolute ethanol, which caused distinctive morphological features, lesions found under the different experimental agents shared a common pattern of progression. Ultrastructural lesions on surface epithelial cells preceded further alterations of parietal cells. After …

Electron Probe Microanalysis Of The Otolithic Membrane. A Methodological And Quantitative Study, J. A. López-Escámez, F. J. Cañizares, P. V. Crespo, A. Campos

Scanning Microscopy

The effect of tissue preparation on calcium and potassium weight percents in the otoconial layer in the utricle and saccule was studied in four groups of OF1 mice with electron probe X-ray microanalysis. Glutaraldehyde and freeze-drying, glutaraldehyde and air-drying, air-drying, and cryo-fixation and freeze-drying were compared. Ca and K changed significantly in the utricle depending on the method used (P < 0.001), and K changed significantly in the saccule (P < 0.001 ). We chose cryo-fixation with freeze-drying for the quantitative analysis of the otolithic membrane because this method provided the highest values of Ca and K with minimum loss of Ca and K . Microcrystalline salt standards mounted on scanning electron microscopy holders were used for the quantification of Ca and K by the peak-to-local-background (P/B) ratio method. The P/B ratio in standards with reproducible results, when plotted against weight percent, gave a straight line for Ca (r = 0.99, P < 0.001) and K (r = 0.98, P < 0.001). The Ca and K weight percents in otoconia showed similar frequency distributions in the utricle and saccule.

Arthropathies Associated With Basic Calcium Phosphate Crystals, Paul B. Halverson

Scanning Microscopy

Basic calcium phosphate (BCP) crystals refer to a family of crystals including partially carbonate substituted hydroxyapatite, octacalcium phosphate, and tricalcium phosphate. These crystals have been found in and around joints and have been associated with several forms of arthritis and periarthritis. Identification of BCP crystals remains problematic because of the lack of a simple, reliable analytic procedure. Methods currently in use include alizarin red S staining, labelled diphosphonate binding, scanning and transmission electron microscopy with energy dispersive X-ray microanalysis, X-ray diffraction, and atomic force microscopy. Periarthropathies associated with BCP crystals include calcific tendinitis and bursitis. Intra-articular BCP crystal deposition is …

The Mayfly Newsletter, Peter M. Grant

The Mayfly Newsletter

The Mayfly Newsletter is the official newsletter of the Permanent Committee of the International Conferences on Ephemeroptera.

Fatigability And Blood Flow In The Rat Gastrocnemius-Plantaris-Soleus After Hindlimb Suspension, Kerry S. Mcdonald, M. D. Delp, Robert H. Fitts

Biological Sciences Faculty Research and Publications

The purpose of this study was to test the hypothesis that hindlimb suspension increases the fatigability of the soleus during intense contractile activity and determine whether the increased fatigue is associated with a reduced muscle blood flow. Cage-control (C) and 15-day hindlimb-suspended (HS) rats were anesthetized, and either the gastrocnemius-plantaris-soleus (G-P-S) muscle group or the soleus was stimulated (100 Hz, 100-ms trains at 120/min) for 10 min in situ. In the G-P-S preparation, blood flow was measured with radiolabeled microspheres before and at 2 and 10 min of contractile activity. The G-P-S fatigued markedly at this stimulation frequency, and the …

Luminal Constrictions On Corrosion Casts Of Capillaries And Postcapillary Venules In Rat Exocrine Pancreas Correspond To Pericyte Processes, Seyedhossein Aharinejad, Peter Böck

Scanning Microscopy

The rat exocrine pancreas was studied as a model to demonstrate morphological features of different types of capillaries, using scanning electron microscopy of vascular corrosion casts and transmission electron microscopy of tissue sections. Two types of capillaries were discerned. The first type represents less undulated, slender, straight capillaries with numerous, shallow, circular or semilunar furrows on its cast's surface. In tissue sections, this type probably corresponds to non-fenestrated capillaries. The numerous grooves on its cast correspond to pericyte processes beneath the endothelial lining. The second type comprises capillaries of an undulated course and variable diameter with less numerous furrows. In …

Appearance Of Venous Sphincters In The Pulmonary Microvascular Bed Of Normotensive And Spontaneously Hypertensive Rats, Seyedhossein Aharinejad, Peter Böck

Scanning Microscopy

The appearance of pulmonary venous sphincters was studied in normotensive and spontaneously hypertensive rats using scanning electron microscopy of microvascular corrosion casts and transmission electron microscopy of tissue sections. Vascular casts were prepared either after lavage with Tyrode solution or after glutaraldehyde prefixation. Pronounced pulmonary venous sphincters were more frequently identified in spontaneously hypertensive rats as compared to corresponding circular indentations in normotensive rats. Tissue sections established venous sphincters in hypertensive animals as consisting of multiple layers of smooth muscle cells in the venous walls. We did not observe any autonomic nerve terminals in close proximity to these bundles of …

Histochemical Demonstration And Microanalysis Of Possible Calcium Binding Sites In The Enamel Organ Of Rat Incisors, Y. Takano

Scanning Microscopy

The rat incisors obtained from rats perfused with high-calcium solution containing 30 to 50 mM CaCl₂ were processed for rapid freeze/freeze-substitution and embedded in epoxy resin. GBHA staining, a histochemical staining for calcium, of unhydrously prepared sections revealed a large number of granular Ca-GBHA reactions in the enamel organ, most of which being located along the lateral plasma membranes of the ameloblasts. In the ameloblast layer, the reaction was negative in the presecretory stage, became intense in concert with the onset of enamel matrix formation, and remained so by the end of the transitional stage where the reaction gradually …