Life Sciences Commons^™

Effect Of Ozone And Calcium Lactate Treaments On Browning And Textured Properties Of Fresh-Cut Lettuce, Daniel Rico, Ana Belen Martin-Diana, Gary Henehan, Jesus Maria Frias, Catherine Barry-Ryan

Articles

The effects of three treatments, 1 mg L⁻¹ ozone at 18–20 °C, 15 g L⁻¹ calcium lactate (CLac) at 50 °C and a combination thereof, were compared on fresh-cut lettuce over 10 days of refrigerated storage. Respiration rate, browning and texture were examined as main quality indicators. The use of ozone produced a significantly (P < 0.05) higher oxygen decline than the use of CLac (from day 3 to day 10). At the end of storage, CLac (alone or combined with ozone) samples had higher oxygen content (∼9%) than ozone samples (∼6%). Enzymatic activity decreased significantly (P < 0.05) in ozone samples. Polyphenol oxidase activity in fresh-cut lettuce treated with ozone (alone or combined with CLac) showed lower values on day 1 (−1) and at the end of storage (g⁻¹) than CLac samples (4000–4800 units g⁻¹). Ozone also reduced peroxidase activity to ∼300 units g⁻¹ after treatment. Finally, pectin methylesterase activity was also reduced with ozone, showing a negative effect on textural properties. Data suggested that …

The Effect Of Protein Dielectric Coefficient On The Ionic Selectivity Of A Calcium Channel, Douglas Henderson, Dezso Boda, Monika Valisko, Bob Eisenberg, Wolfgang Nonner, Dirk Gillespie

Faculty Publications

Calcium-selective ion channels are known to have carboxylate-rich selectivity filters, a common motif that is primarily responsible for their high Ca2+ affinity. Different Ca2+ affinities ranging from micromolar (the L-type Ca channel) to millimolar (the ryanodine receptor channel) are closely related to the different physiological functions of these channels. To understand the physical mechanism for this range of affinities given similar amino acids in their selectivity filters, we use grand canonical Monte Carlo simulations to assess the binding of monovalent and divalent ions in the selectivity filter of a model Ca channel. We use a reduced model where the electrolyte …

Emerging Physiological Significance Of R-Type Calcium Currents, Paul Jensen

Undergraduate Honors Capstone Projects

R-type channels are voltage dependent calcium channel subtypes. To date, the only variant of the R-type calcium channel that has been isolated and cloned is the Ca_v2.3 variant, encoded by the gene Cchral (Yamazaki et al., 1998). The channel was named "R-type" because it was initially characterized by its resistance to nifedipine (a blocker of L-type calcium channels), Ω-conotoxin GVIA (an N-type calcium channel blocker) and Ω -Aga IVA (a blocker of P/Q-type calcium channels) (Hille 2001). The Ca_v2.3 calcium channel is selectively inhibited by the peptide SNX-482, which was isolated from venom of the African …

Radial Spoke Proteins Of Chlamydomonas Flagella, Pinfen Yang, Dennis R. Diener, Chun Yang, Takahiro Kohno, Gregory J. Pazour, Jennifer M. Dienes, Nathan S. Agrin, Stephen M. King, Winfield S. Sale, Ritsu Kamiya, Joel L. Rosenbaum, George B. Witman

Biological Sciences Faculty Research and Publications

The radial spoke is a ubiquitous component of `9+2' cilia and flagella, and plays an essential role in the control of dynein arm activity by relaying signals from the central pair of microtubules to the arms. The Chlamydomonas reinhardtii radial spoke contains at least 23 proteins, only 8 of which have been characterized at the molecular level. Here, we use mass spectrometry to identify 10 additional radial spoke proteins. Many of the newly identified proteins in the spoke stalk are predicted to contain domains associated with signal transduction, including Ca²⁺-, AKAP- and nucleotide-binding domains. This suggests that the …

The Involvement Of Calcium And Map Kinase Signaling Pathways In The Production Of Radiation-Induced Bystander Effects, Fiona Lyng, Paula Maguire, B. Mcclean, C. Seymour, Carmel Mothersill

Articles

Much evidence now exists regarding radiation-induced bystander effects, but the mechanisms involved in the transduction of the signal are still unclear. The mitogen-activated protein kinase (MAPK) pathways have been linked to growth factor-mediated regulation of cellular events such as proliferation, senescence, differentiation and apoptosis. Activation of multiple MAPK pathways such as the ERK, JNK and p38 pathways have been shown to occur after exposure of cells to radiation and a variety of other toxic stresses. Previous studies have shown oxidative stress and calcium signaling to be important in radiation-induced bystander effects. The aim of the present study was to investigate …

Stretch-Dependant Tonic Force Maintenance In Rabbit Epigastric Artery, Krystina Michelle Berg

Theses and Dissertations

The contractile state of vascular smooth muscle (VSM) plays a key role in blood pressure regulation. Abnormal VSM contractility characterizes hypertension and understanding the regulatory mechanisms of VSM may provide some insights to specific treatment of hypertension. Upon muscle stimulation, Ca2+, myosin light chain (MLC) phosphorylation, crossbridge cycling rates and force increase to high levels, but with time, force is maintained while all other parameters of muscle activation fall to low levels. Thus, contraction is divided temporally into early (phasic) and late (tonic) phases, as determined by the underlying regulatory mechanism. Muscles with more phasic characteristics have a higher peak …

Ec06-155 Nutrient Management For Agronomic Crops In Nebraska, Richard B. Ferguson

University of Nebraska-Lincoln Extension: Historical Materials

Nebraska is blessed with fertile soil and vast supplies of groundwater which combine to create an environment well-suited to the production of corn, wheat, grain sorghum, alfalfa, edible beans, and other agronomic crops used for human or animal consumption.

This manual is a guide to nutrient use from all sources for the production of Nebraska's major agronomic crops: corn, winter wheat, grain sorghum, oats, alfalfa, dry edible beans, soybean, sugar beets, popcorn, sunflower, millet, potatoes, and cool and warm season grasses for hay and pasture. Part I of the manual contains information focusing on basic principles of soil fertility for …