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Full-Text Articles in Life Sciences
Porophyllum Pygmaeum (Asteraceae), A Distinctive New Species From Southern Nevada, David J. Keil, James D. Morefield
Porophyllum Pygmaeum (Asteraceae), A Distinctive New Species From Southern Nevada, David J. Keil, James D. Morefield
Biological Sciences
Porophyllum pygmaeum is a new species from coarse calcareous soils of the Desert National Wildlife Range in Clark Co., Nevada. It has subterete leaves that contain a continuous double layer of palisade mesophyll surrounding a central area of larger, achlorophyllous, polyhedral parenchyma cells and veins. The hollow foliar oil glands lie just below the abaxial epidermis and are deeply invaginated within the parenchyma layers. Porophyllum pygmaeum is a tetraploid (n = 24) perennial herb that apparently is most closely related to P. greggii a hexaploid herbaceous species of western Texas with much longer and narrower leaves. In its fleshy subterete …
Dynamics Of Mitochondrial Dna Evolution In Animals: Amplification And Sequencing With Conserved Primers, T. D. Kocher, W. K. Thomas, A. Meyer, S. V. Edwards, S. Pääbo, F. X. Villablanca, A. C. Wilson
Dynamics Of Mitochondrial Dna Evolution In Animals: Amplification And Sequencing With Conserved Primers, T. D. Kocher, W. K. Thomas, A. Meyer, S. V. Edwards, S. Pääbo, F. X. Villablanca, A. C. Wilson
Biological Sciences
With a standard set of primers directed toward conserved regions, we have used the polymerase chain reaction to amplify homologous segments of mtDNA from more than 100 animal species, including mammals, birds, amphibians, fishes, and some invertebrates. Amplification and direct sequencing were possible using unpurified mtDNA from nanogram samples of fresh specimens and microgram amounts of tissues preserved for months in alcohol or decades in the dry state. The bird and fish sequences evolve with the same strong bias toward transitions that holds for mammals. However, because the light strand of birds is deficient in thymine, thymine to cytosine transitions …
Identification Of Cyclic Intermediates In Azorhizobium Caulinodans Nicotinate Catabolism, Christopher Kitts, Lisa E. Schaechter, Ross S. Rabin, Robert A. Ludwig
Identification Of Cyclic Intermediates In Azorhizobium Caulinodans Nicotinate Catabolism, Christopher Kitts, Lisa E. Schaechter, Ross S. Rabin, Robert A. Ludwig
Biological Sciences
In wild-type Azorhizobium caulinodans ORS571, nicotinate served both as anabolic substrate for NAD+ production and as catabolic substrate for use as the N source. Catabolic enzyme activities were greatest from cultures grown with nicotinate as the N source and least when cultures were grown with ammonium as the N source. Vector insertion mutants unable to catabolize nicotinate (nic::Vi mutants) still required micromolar quantities of this compound for growth. Therefore, A. caulinodans wild type is NAD+ auxotrophic. As the first two intermediates in A. caulinodans nicotinate catabolism, two cyclic compounds, 6-hydroxynicotinate and 1,4,5,6-tetrahydro-6-oxonicotinate, were identified. These compounds …
Annual Variation Of Estuarine And Oceanic Oyster Crassostrea Virginica Gmelin Hemocyte Capacity, William S. Fisher, Marnita M. Chintala, Mark A. Moline
Annual Variation Of Estuarine And Oceanic Oyster Crassostrea Virginica Gmelin Hemocyte Capacity, William S. Fisher, Marnita M. Chintala, Mark A. Moline
Biological Sciences
Defense-related hemocyte activities of American oysters Crassostrea virginica Gmelin from an oceanic and an estuarine habitat were monitored from spring to winter of 1987 at a constant temperature (15 °C). The ability of cells to spread to an ameboid shape in vitro at ambient salinity and after an acute change in salinity was much reduced from late spring to early fall. This summer-stress period was also indicated by laboratory experiments. Stress may have been due to high water temperatures but spawning efforts may have also contributed. Reduced hemocyte activity occurred at a time when infections by two major oyster parasites …
Changes With Time In The Availability Of Soil Applied Zinc To Navy Beans And In The Chemical Extraction Of Zinc From Soils, J. D. Armour, G. S.P. Ritchie, A. D. Robson
Changes With Time In The Availability Of Soil Applied Zinc To Navy Beans And In The Chemical Extraction Of Zinc From Soils, J. D. Armour, G. S.P. Ritchie, A. D. Robson
Food Science and Nutrition
The effect of the incubation of zinc (Zn) applied to the soil on Zn uptake and the Zn concentrations in chemical extractants was studied. In a glasshouse experiment using a Zn-deficient gravelly sandy loam, the effect of recently applied Zn was compared with that of Zn incubated with the soil for 15 days at 40°C on growth and Zn uptake by navy beans (Phaseolus vulgaris cv. Gallaroy). At the second harvest (33 days after sowing), the dry weight of shoots of recently applied Zn was consistently higher than that of incubated Zn, except at the highest rate of 1 …
Melamine/Urea And Oxamide Fertilization Of Kentucky Bluegrass, David J. Wehner, Dennis L. Martin
Melamine/Urea And Oxamide Fertilization Of Kentucky Bluegrass, David J. Wehner, Dennis L. Martin
Office of the Dean (CAFES) Scholarship
The commercial lawn care industry represents a large market for N sources. A formulated melamine (2,4,6-triamino-s-triazine) plus urea combination (MLU) (45% melamine by weight) and oxamide were evaluated for use by the lawn care industry by comparing turfgrass response from these fertilizers to that from urea, sulfur coated urea (SCU), ureaformaldehyde (Nitroform), and a non-fertilized check. Fertilizers were applied four times per year to field plots of Kentucky bluegrass (Poa pratensis L.) growing on a Flanagan silt loam (fine, montmorillonitic, mesic Aquic Argiudoll) at a rate of 49 kg N ha-1 per application. Color ratings and clipping weights …
Plant Photosensitizers: A Survey Of Their Occurrence In Arid And Semiarid Plants From North America, Kelsey R. Downum, Sergio Villegas, Eloy Rodriguez, David J. Keil
Plant Photosensitizers: A Survey Of Their Occurrence In Arid And Semiarid Plants From North America, Kelsey R. Downum, Sergio Villegas, Eloy Rodriguez, David J. Keil
Biological Sciences
No abstract provided.