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T W Seale

Publications and source records attributed to T W Seale.

61 records · Page 4Linked to original sources
PubMed1974

Liberation and development of Allomyces arbuscula mitospores viewed by scanning electron microscopy.

Scanning electron microscopy has been employed to examine events in the release and development of mitospores of the aquatic fungus, Allomyces arbuscula. Among the salient features of spore release from the mitosporangium is the digestion of the inner matrix of the exit papillum. Hydrolysis appears to begin at the outer layer of the papillum plug matrix and probably results from activation of localized hydrolytic enzymes. The plug clearly consists of at least two different component layers. Elaboration of mitospores from the mitosporangium is depicted in several micrographs. Motile spores were induced to begin development, and the sequence of surface changes associated with the encystment process was studied. Time course studies show the retraction of the flagellum, the change from elipsoidal to spherical shape, and the deposition of the cell wall. Early in encystment, small vesicles accumulate on the surface of the plasma membrane. These enlarge and fuse to form the mature cyst wall. This surface view of cell wall deposition appears to support the possible role of gamma particles in cell wall synthesis during encystment.

Cell Membrane↗
PubMed1972

Protein and ribonucleic acid synthesis during the diploid life cycle of Allomyces arbuscula.

The diploid life cycle of Allomyces arbuscula may be divided into four parts: spore induction, germination, vegetative growth, and mitosporangium formation. Spore induction, germination, and mitosporangium formation are insensitive to inhibition of actinomycin D, probably indicating that stable, pre-existing messenger ribonucleic acid (RNA) is responsible for these developmental events. Protein synthesis is necessary during the entire life cycle except for cyst formation. A system for obtaining synchronous germination of mitospores is described. During germination there is a characteristic increase in the rate of synthesis of RNA and protein although none of the other morphogenetic changes occurring during the life cycle are necessarily accompanied by an appreciable change in the rate of macromolecular synthesis.

Adenine↗
PubMedDate not supplied

Reproductive defects in patients of both sexes with cystic fibrosis: a review.

Current knowledge of reproductive duct function in both male and female cystic fibrosis patients is reviewed. Almost all male patients are sterile because of azoospermia. The mechanistic basis of the obstructive defect leading to pre- and post-natal destruction of selected portions of the sperm-conducting network remains unknown. Female cystic fibrosis patients are fertile. Pulmonary status appears to be the most important factor in determining pregnancy outcome. In contrast to earlier concerns about the normality of breast milk, breast milk composition of cystic fibrosis mothers is normal, and they can successfully breast feed their infants.

Adolescent↗
PubMedDate not supplied

Prenatal diagnosis of thalassemias and hemoglobinopathies.

Thalassemia syndromes and hemoglobinopathies are of clinical genetic significance because of the severity of the sequelae associated with particular genetic constitutions in these conditions, their occurrence at high frequencies in certain populations of Mediterranean, African, and Asian origin, and the high frequency of recurrence in pregnancies of at risk families. Application of recently developed techniques of molecular genetics to the antenatal diagnosis of the most deleterious of these conditions (homozygous beta-thalassemia [Cooley's anemia], homozygous alpha-thalassemia [Barts hydrops fetalis], sickle cell anemia, and related severe homoglobinopathies) now affords parents the option to interrupt a pregnancy in which the fetus has the genetic constitution causing one of these abnormalities. The two different analytical strategies utilize fetal cells obtained by aminocentesis. In one, fetal blood is obtained either by sonographically guided placental aspiration or by aspiration from a placental vein directed by fetoscopy. Globin chain synthesis is monitored by the incorporation of radiolabelled amino acids in the isolated erythrocytes and the determination of the ratio of radioactive label incorporated into the various globin chains separated by column chromatography or electrophoresis. This technique is applicable to the antenatal diagnosis of alpha-and beta-thalassemia and to selected hemoglobinopathies. However, in the most experienced centers, fetal blood sampling is associated with a greatly increased risk of fetal loss. The other analytical approach utilizes desoxyribonucleic acid (DNA) isolated from fibroblasts to evaluate the presence of quantitatively and/or qualitatively normal DNA sequences, which constitute the structural gene(s) encoding specific globin polypeptide chains. This approach is most generally applicable to the detection of structural gene deletions as in a alpha-thalassemia; maternal and fetal risk is the same as that for conventional amniocentesis.

Amniotic Fluid↗