Open Access. Powered by Scholars. Published by Universities.®

Life Sciences Commons™

Open Access. Powered by Scholars. Published by Universities.®

Biology

Selected Works

1991

Articles 1 - 6 of 6

Full-Text Articles in Life Sciences

The Alpha-Adrenergic Stimulation Of Atrial Natriuretic Factor Expression In Cardiac Myocytes Requires Calcium Influx, Protein Kinase C, And Calmodulin-Regulated Pathways, C A. Sei, C E. Irons, A B. Sprenkle, P M. Mcdonough, J H. Brown, C C. Glembotski Aug 1991

The Alpha-Adrenergic Stimulation Of Atrial Natriuretic Factor Expression In Cardiac Myocytes Requires Calcium Influx, Protein Kinase C, And Calmodulin-Regulated Pathways, C A. Sei, C E. Irons, A B. Sprenkle, P M. Mcdonough, J H. Brown, C C. Glembotski

Amy Sprenkle

It has been shown recently that a-adrenergic agonists can stimulate atrial natriuretic factor (ANF) expression in ventricular cardiac myocytes; however, little is known about the intracellular signals mediating this activation. The present study focused on the potential roles of calcium-regulated kinases and calcium influx in the a-adrenergic stimulation of ANF gene expression in ventricular myocardial cell cultures. Myocardial cells maintained for 48 h in serumfree medium supplemented with phenylephrine (PE) possessed up to 15-fold higher levels of ANF peptide and ANF mRNA than control cells. The removal of PE, or the addition of nifedipine, resulted in a rapid decline in …

Go to article

Changes In Hydraulic Conductivity And Anatomy Caused By Drying And Rewetting Roots Of Agave Deserti (Agavaceae), Gretchen North, P. Nobel Dec 1990

Changes In Hydraulic Conductivity And Anatomy Caused By Drying And Rewetting Roots Of Agave Deserti (Agavaceae), Gretchen North, P. Nobel

Gretchen North

Concurrent determinations of changes in hydraulic conductivity and tissue anatomy were made for roots of Agave deserti excised during drying and following rewetting in soil. At 30 d of drought, hydraulic conductivity had declined less than twofold for older nodal roots, tenfold for young nodal roots, and more than 20-fold for lateral roots ("rain roots" occurring as branches on the nodal roots). These decreases were consistent with increases in cortical lacunae caused by cell shrinkage and collapse. Similarly, reduction of lacunae in response to rewetting after 7 d of drought corresponded to levels of recovery in hydraulic conductivity, with young …

Go to article

Clonal Integration: Nutrient Movement Between Sister Ramets Of Solidago Altissima, W. Abrahamson, S. Anderson, K. Mccrea Dec 1990

Clonal Integration: Nutrient Movement Between Sister Ramets Of Solidago Altissima, W. Abrahamson, S. Anderson, K. Mccrea

Warren G. Abrahamson, II

No abstract provided.

Go to article

An Evolutionary Perspective On Salt, Hypertension, And Human Genetic Variability, Fatimah Linda Collier Jackson Dec 1990

An Evolutionary Perspective On Salt, Hypertension, And Human Genetic Variability, Fatimah Linda Collier Jackson

Fatimah Linda Collier Jackson

Natural selection for electrolyte conservation has likely been the norm throughout human evolutionary history. However, the current patterns of excessive dietary salt intake create the potential for salt overload. Under these conditions, hypertension may be considered an expected pathological response to an evolutionarily new constraint. The transatlantic Middle Passage may have created a genetic bottleneck for salt conservation in African-Americans. Although the initial consequences of this important historical event probably constricted genetic variability and further magnified the potential for salt-sensitive hypertension, the Middle Passage undoubtedly also served as a more generalized major source of environmental stress and may have stimulated …

Go to article

Review Essay Of Two Books On The History Of Science, Charles Kay Smith Dec 1990

Review Essay Of Two Books On The History Of Science, Charles Kay Smith

Charles Kay Smith

Contrary to what I was taught in high school in the mid-1940s, science is no longer defined as an inductive methodology for immaculately conceiving culture-free truth after sifting through a huge data base of objective facts. For without some prior hypothesis to guide her, a scientist would not be able to decide which facts were relevant. Nowadays hypotheses can come from anywhere in the imagination or culture within which the scientist is working. The importance of a scientific hypothesis is that it be framed in such a way that it can be falsified when tested. Science now has a history …

Go to article

Abnormal Chromatin (Abc), A Maternal-Effect Locus In Drosophila Melanogaster, Kristin B. Vessey, Rachael L. Ludwiczak, Amy S. Briot, Eileen M. Underwood Dec 1990

Abnormal Chromatin (Abc), A Maternal-Effect Locus In Drosophila Melanogaster, Kristin B. Vessey, Rachael L. Ludwiczak, Amy S. Briot, Eileen M. Underwood

Eileen M. Underwood

Mutations in the maternal-effect gene abnormal chromatin (abc) in Drosophila melanogaster result in a variety of defects involving nuclear replication/division. Three recessive alleles of this gene, which maps near 51F on chromosome 2, all result in female sterility. They cause slower embryonic development that is usually abnormal from the earliest nuclear divisions and arrested by the sixth one. Nuclei tend to be large and erratically distributed, some intensely staining. Mitotic asynchrony is common. Few embryos reach the gastrula stage and none hatch. With the weakest allele, fsPL, bridges between nuclei are common; abnormal chromatin clumps that resemble yolk nuclei occur …

Go to article