Physical Sciences and Mathematics Commons^™

The Effect Of Divalent Cations On The Prophenoloxidase Enzyme Cascade Activity In The Freshwater Crayfish Cambarus Latimanus, Hans Skailand Eikaas

Theses and Dissertations

The effect of divalent cations such as cadmium, calcium, copper, lead and magnesium upon the prophenoloxidase system (proPO) was studied in hemocytes of the crayfish Cambarus latimanus. It was demonstrated that cadmium, calcium, copper and lead increased proPO activity significantly, whereas magnesium had no statistically significant effect on the system. Also, the molecular weight of the proPO enzyme was estimated using SDS-PAGE and found to be approximately 76 kDa.

In-Situ Measurement Of Denitrification In The Elk Valley Aquifer, Allen Schlag

Theses and Dissertations

Groundwater serves more than half of North Dakota's population as a drinking water source. Nitrate (NO₃¯) is a common groundwater contaminant associated with fertilizers, septic systems and livestock waste in shallow unconfined aquifers. As a suspected carcinogen and cause of potentially lethal methemoglobinemia in infants, the natural attenuation of NO₃¯ by denitrification can be an important process in keeping groundwater as a reliable source of clean drinking water for North Dakota. Organic carbon is often considered the most important electron donor for the chemical reduction of NO₃¯ into harmless nitrogen gas. However, several studies have shown that inorganic electron donors …

Description And Taphonomy Of A Turtle Assemblage (Chelonia: Trionychidae) In The Sentinel Butte Formation (Paleocene), Billings County, North Dakota, Glenn B. Kays

Theses and Dissertations

Soft-shelled turtle fossils (Family: Trionychidae) are common in Late Mesozoic and Early Cenozoic freshwater terrestrial deposits throughout western North America. Taxonomy of the Trionychidae is confusing for two reasons: 1) there are differences of opinion as to which characters are important in defining the lower systematic groups; 2) trionychid fossil material is often incomplete and fragmentary and has been used as the basis for numerous taxonomic descriptions.

The Ash Coulee Quarry is a fossil turtle assemblage located within the lower portion of the Sentinel Butte Formation (Paleocene) in Billings County, North Dakota. This quarry has produced at least 40 individual …