Norman E. Williams

University of Iowa

Author Statistics

Papers

Citation

H-Index

i-10 index

Research Trends

Author Order

Document Type

Co-Authors

Jerry E. Honts

Drake University

Joseph Frankel

University of Iowa

Doris H. Clouet

New York State Office of Alcoholism and Substance Abuse Services

E. Marlo Nelsen

Park Nicollet Methodist Hospital

Virginia M. Dress

University of Arizona

Howard G. Bruenn

Presbyterian Hospital

Pierre Vaudaux

University Hospital of Geneva

Hong Yi

Xiangya Hospital Central South University

F. Paul Doerder

Cleveland State University

Robert L. Levy

Woodhull Medical and Mental Health Center

Cooperative Institutions

University of Iowa

The University of Texas at Austin

University College London

Queen Charlotte's and Chelsea Hospital

State University of New York

University of Illinois Urbana-Champaign

University of Southampton

SUNY Downstate Health Sciences University

University of Wisconsin–Madison

New York State Office of Alcoholism and Substance Abuse Services

Author Statistics

Papers

Citation

H-Index

i-10 index

Research Field

REGULATION OF MICROTUBULES IN TETRAHYMENA

The Journal of Cell Biology (1973)

Norman E. Williams Joseph Frankel

The coupled resorption and redifferentiation of oral structures which occurs in Tetrahymena pyriformis under conditions of amino acid deprivation has been studied by transmission electron microscopy. Two patterns of ciliary resorption have been found, (a) in situ, and (b) after withdrawal into the cytoplasm. No autophagic vacuoles containing cilia or ciliary axonemes have been seen. Stomatogenic field basal bodies arise by a process of rapid sequential nucleation, with new ones always appearing next to more mature ones, even though the latter may not be fully differentiated. Accessory radial ribbons of microtubules develop immediately adjacent to oral field basal bodies as a late step in their maturation. It can be seen that the formation of basal bodies and their orientation within the oral complex are separate processes. This is true for about 130 of the approximately 170 oral basal bodies; the remaining 40 or so form within the patterned groups of ciliary units as a later event. Clusters of randomly oriented thin-walled microtubules are found surrounding oral basal bodies at all times during stomatogenesis. They may either represent stores of microtubule subunit protein, or serve as effectors of basal body movement during their orientation into pattern.

Basal body

Tetrahymena pyriformis

Basal (medicine)

10.1083/jcb.56.2.441

Cite

Citations (71)

Polymorphism in Tetrahymena vorax*

The Journal of Protozoology (1961)

Norman E. Williams

Two types of polymorphism, differing greatly in stability characteristics, have been recognized in Tetrahymena vorax strain V2. The basic life history involves three stages: a microstome, a macrostome, and a cyst. The appearance of each of these stages is dependent upon conditions of substrate availability, i.e. , macrostomes persist in the presence of suitable ciliate prey, microstomes persist in the presence of bacteria or organic nutrient solutions, and cysts appear under conditions of starvation. Superimposed upon the basic life history is a second level of polymorphism: three markedly different types of sublines have been obtained from a single parental clone. No intermediate types have been observed. When grown under identical controlled conditions, the three types of sublines differ significantly in cell and nuclear size, meridian number, growth properties, competence to form cysts and macrostomes, and serotype. Each subline of a given type is subject to transformation into one or both of the other types. These transformations are usually spontaneous events with very low frequencies, although certain transformations may be induced. Once a transformation has occurred, the new phenotype is inherited by subsequent generations of cells for an indefinite period in a way which is independent of environmental influences. The available information suggests that the three types of sublines are not the result of gene mutations, but rather represent alternate epigenetic stable states of a single cellular system.

10.1111/j.1550-7408.1961.tb01235.x

Cite

Citations (65)

Use of a nitrogen mustard derivative in fixation for electron microscopy and observations on the ultrastructure of Tetrahymena

Journal of Ultrastructure Research (1968)

Norman E. Williams John H. Luft

Tetrahymena pyriformis

Basal body

Glutaraldehyde

Nitrogen mustard

Ciliata

Fragmentation

10.1016/s0022-5320(68)80074-7

Cite

Citations (108)

Formation and positioning of surface-related structures in protozoa

Microbiological Reviews (1980)

K J Aufderheide Joseph Frankel Norman E. Williams

10.1128/mr.44.2.252-302.1980

Cite

Citations (104)

Variation In Surface Proteins In Tetrahymena*

The Journal of Protozoology (1980)

Norman E. Williams Carol Bell Michael C. Newlon

Surface proteins of Tetrahymena were identified by lactoperoxidase iodination, and comparisons were made between a number of strains and species within the genus. An adequate procedure for strain comparisons was found to be solubilization of whole cells following iodination, separation of total cell protein using polyacrylamide gel electrophoresis, and identification of surface proteins by autoradiography of dried gels. The results obtained in the present study show the existence of both interspecific and intraspecific variation in surface proteins of tetrahymena, but the differences tend to be small within species and large between species. The relation of these cell surface fingerprints to the present taxonomic designations within the genus is discussed. Questions are raised about the functional significance of these surface proteins.

Lactoperoxidase

10.1111/j.1550-7408.1980.tb04276.x

Cite

Citations (12)

Membrane Protein Differences Correlated with the Development of Mating Competence in Tetrahymena thermophila1

The Journal of Protozoology (1984)

Craig T. Van Bell Norman E. Williams

ABSTRACT Initiation is the contact‐independent phase of sexual conjugation which occurs when mature cells of Tetrahymena thermophila are shifted from growth medium to a low‐salt starvation buffer. Immaturity, like high‐salt starvation, restricts the ability of cells to conjugate; immature cells do not conjugate in either low‐ or high‐salt buffers. Comparisons between sexually mature cells starved in initiation‐restrictive and initiation‐permissive buffers, and between immature and mature cells starved in an initiation‐permissive buffer permitted the analysis of membrane protein expression correlated with mating competence. No polypeptides identified by lactoperoxidase‐catalyzed iodination were found to be specific to mating‐competent cells; however, several polypeptides not present in initiated cells were found to be common to the cell surfaces of immature and non‐initiated cells which suggests that (1) initiation involves the removal of specific proteins from the cell surface, and (2) immaturity may be due to an inability to initiate.

10.1111/j.1550-7408.1984.tb04299.x

Cite

Citations (8)

Is cyclin Zeuthen's “division protein”?

Experimental Cell Research (1991)

Norman E. Williams Michelle G. Macey

Tetrahymena pyriformis

Cyclin B

10.1016/0014-4827(91)90414-p

Cite

Citations (13)

388. The ether-soluble constituents of sarsaparilla root. Part II

Journal of the Chemical Society (Resumed) (1938)

J. C. E. Simpson Norman E. Williams

J. C. E. Simpson and N. E. Williams, J. Chem. Soc., 1938, 2040 DOI: 10.1039/JR9380002040

Root (linguistics)

10.1039/jr9380002040

Cite

Citations (1)

Application of direct bias control in high-density inductively coupled plasma etching equipment

Journal of Vacuum Science & Technology A Vacuum Surfaces and Films (2000)

Roger Patrick Scott Baldwin Norman E. Williams

The use of a novel method of power delivery control at the wafer chuck in a high-density inductively coupled plasma reactor has been investigated. This method involves using a peak voltage sensor mounted immediately below the chuck in a feedback loop to the rf generator such that the rf peak voltage can be set as a recipe parameter. By controlling the power delivery in this manner, it is demonstrated that the effects of power losses in the rf circuit between the generator and the chuck, especially in the match network, can be compensated for. In addition, the effect of interactions among source power, bias power and other process parameters on sheath voltage can also be eliminated. In this manner a more complete decoupling of plasma density and ion energy can be achieved than more conventional methods of power delivery allow.

Decoupling (probability)

Plasma Etching

Power density

Biasing

10.1116/1.582201

Cite

Citations (25)

Morphogenetic Events in Normal and Synchronously Dividing Tetrahymena

Development (1959)

Norman E. Williams Otto H. Scherbaum

ABSTRACT A study of differentiation in the ectoplasmic cortex of T. pyriformis GL subjected to the standard temperature cycling for the induction of synchronous binary fission has demonstrated an arrest in development which occurs in all cells at a characteristic point in the cell cycle. After treatment all cells were found to possess anarchic fields of kinetosomes in the stomatogenic region, indicating 100 per cent, synchrony. The cells remain in this condition for a period of 50 –55 minutes after the last heat shock. During this time no changes other than in increase in the size of the macronuclear chromatin granules could be detected. At the end of the period of arrested development morphogenesis resumes and binary fission continues in synchrony. The degree of synchrony is somewhat reduced as development proceeds, resulting in about 85 per cent, synchrony at the time of cytoplasmic constriction. In order to facilitate analysis of morphogenesis in synchronously dividing Tetrahymena, a series of four developmental stages has been defined. Based on work which has confirmed available descriptions of stomatogenesis and macronuclear fission, the sequence includes new data on development of the somatic ciliature. All observations, including quantitative consideration of the somatic kinetosomes, ciliary meridians, and contractile vacuole pores has indicated that, aside from synchrony and the period of arrested development, the morphogenetic events in synchronized organisms are fundamentally no different from these processes in untreated cultures. Growth of the organism, growth of the macronucleus, and morphogenesis are to some extent dissociated in synchronized cultures of Tetrahymena. During the heat treatment morphogenesis is blocked while cell and macronuclear growth continues. After treatment and prior to the synchronous cytoplasmic constriction there is a significant increase in mean nuclear volume with no significant increase in total cell volume. After resumption of development in synchronized cultures morphogenesis proceeds unaccompanied by any increase in cellular volume. In addition, it is believed that the nuclear increase occurs during the period of arrested development and not during the subsequent period of development. The use of protargol staining promises to be of value in studies of ciliate morphogenesis. Of those structures in and on the ciliate cortex, protargol appears to be highly specific for kinetosomes. In addition to this the cilia and ciliary membranes are revealed by this technique.

Macronucleus

Basal body

10.1242/dev.7.2.241

Cite

Citations (32)