Biology Commons^™

Parallel Adaptation Of Cd4 In Siv-Endemic Gorilla And Pan Lineages, Katie E. Brown

Biological Sciences

The simian immunodeficiency virus (SIV) is homologous to the human immunodeficiency virus (HIV), and naturally infects chimpanzees and gorillas in the wild. Some African primate species appear to have evolved resistance to SIV, in that the virus no longer is found in the species or, if infected, individuals within the species show no serious symptoms of simian AIDS (SAIDS). In contrast, Asian primate species do not appear to naturally harbor SIV and, like humans, often progress to AIDS following infection. CD4 is the primary T cell receptor that SIV/HIV interacts with to infect host T cells. Domain 1 (D1) of …

Diversity And Soil-Tissue Elemental Relations Of Vascular Plants Of Callahan Mine, Brooksville, Maine, U.S.A., Margaret R. Mansfield, Nathaniel S. Pope, Glen H. Mittelhauser, Nishanta Rajakaruna

Biological Sciences

Metal-contaminated soils provide numerous stressors to plant life, resulting in unique plant communities worldwide. The current study focuses on the vascular plants of Callahan Mine in Brooksville, ME, USA, a Superfund site contaminated with Cu, Zn, Pb, and other pollutants. One hundred and fifty-five taxa belonging to 50 families were identified, with the Asteraceae (21%), Poaceae (11%), and Rosaceae (9%) as the most species-rich families. Ninety-six species encountered at the Mine were native to North America (62%), including 11 taxa (7%) with rarity status in at least one New England state. Fifty-one species were non-native (33%), including nine taxa (6%) …

Metal Release From Serpentine Soils In Sri Lanka, Meththika Vithanage, Anushka Upamali Rajapaksha, Christopher Oze, Nishanta Rajakaruna, C. B. Dissanayake

Biological Sciences

Ultramafic rocks and their related soils (i.e., serpentine soils) are non-anthropogenic sources of metal contamination. Elevated concentrations of metals released from these soils into the surrounding areas and groundwater have ecological-, agricultural-, and human health-related consequences. Here we report the geochemistry of four different serpentine soil localities in Sri Lanka by coupling interpretations garnered from physicochemical properties and chemical extractions. Both Ni and Mn demonstrate appreciable release in water from the Ussangoda soils compared to the other three localities, with Ni and Mn metal release increasing with increasing ionic strengths at all sites. Sequential extraction experiments, utilized to identify “elemental …

In Vivo Analysis Of Riboswitch Activity Using Luciferase Assays, Jason Kartis

Biological Sciences

Riboswitches are a type of RNA structure found on messenger RNAs that function in gene expression regulation. The preQ1 riboswitch is particularly interesting to study because it contains a relatively small aptamer binding region and it is not essential in E. coli for the organism's survival, allowing in vivo experimentation in a viable organism. Upon ligand binding to the aptamer, a hairpin-type RNA pseudoknot forms, which functions to turn off the gene using a premature transcriptional termination mechanism. However, in some species studied, this terminator hairpin possesses enough thermodynamic stability that it is doesn't unfold upon release of the ligand. …

Using Crossword Puzzles To Enhance Students' Learning Of Technical Biological Terms, William D. Stansfield

Biological Sciences

No abstract provided.

The Role Of Elevation And Soil Chemistry In The Distribution And Ion Accumulation Of Floral Morphs Of Streptanthus Polygaloides Gray (Brassicaceae), A Californian Nickel Hyperaccumulator, Nathaniel S. Pope, Michael Fong, Robert S. Boyd, Nishanta Rajakaruna

Biological Sciences

Background: The flora of serpentine/ultramafic soils provides an excellent model system for the study of natural selection in plant populations. Streptanthus polygaloides is a nickel hyperaccumulator that is endemic to serpentine soils in the Sierra Nevada of California, and has four floral morphs (yellow, purple, yellow-to-purple and undulate).

Aims: We investigate three hypotheses: (1) the purple morph occurs in colder, wetter climates than the yellow morph; (2) tissue–soil ionic relationships differ among morphs; and (3) morphs occur on soils with differing elemental concentrations.

Methods: We queried herbarium records to investigate patterns of occurrence among the yellow and purple floral morphs, …

Little Evidence For Local Adaptation To Soils Or Microclimate In The Post-Fire Recruitment Of Three Californian Shrubs, Annette Bieger, Nishanta Rajakaruna, Susan Harrison

Biological Sciences

Background: Seedling recruitment following fire is an infrequent yet critical demographic transition for woody plants in Mediterranean ecosystems.

Aims: Here we examine whether post-fire seedling recruitment of three widespread Californian chaparral shrubs is affected by local adaptation within an edaphically and topographically complex landscape.

Methods: We reciprocally transplanted 6-month-old seedlings of Adenostema fasciculatum, Ceanothus cuneatus and Eriodictyon californicum to serpentine and sandstone soils, and cool northerly and warm southerly slopes.

Results: At the age of 2 years, none of the species manifested higher survival or growth on ‘home’ compared with ‘away’ soils or slopes, indicating an absence of local …