Life Sciences Commons^™

Effects Of Litter On Seedling Emergence And Seed Persistence Of Three Common Species On The Loess Plateau In Northwestern China, Rui Zhang, Xiaowen Hu, Jerry M. Baskin, Carol C. Baskin, Yanrong Wang

Biology Faculty Publications

Litter accumulation resulting from land use change (enclosure) is one of the key variables influencing seedling recruitment and consequently the regeneration of plant populations and seed persistence in the soil seed bank. A better understanding of the effects of litter on seed germination and seedling emergence is crucial for developing a new set of indicators for grassland ecosystem health and for grassland management policy. We investigated the effects of seed position in litter and amount of litter covering the seed on seedling emergence and seed persistence of three common species on the Loess Plateau in northwestern China. Seed position beneath …

Seed Dormancy-Breaking In A Cold Desert Shrub In Relation To Sand Temperature And Moisture, Huiliang Liu, Buhailiqiemu Abudureheman, Lingwei Zhang, Jerry M. Baskin, Carol C. Baskin, Daoyuan Zhang

Biology Faculty Publications

Seasonal periodicity of seed germination and its relationship to seasonal changes in temperature and soil moisture have been well studied in seeds of species with physiological dormancy. However, relatively little information is available on the role of these environmental factors in controlling germination of seeds with physical dormancy (PY). Our primary aim was to determine if seeds of the cold desert sand dune semi-shrub Eremosparton songoricum exhibits seasonal periodicity of seed germination and the relationship between seed dormancy break and soil temperature and moisture. In the laboratory, seeds incubated on dry, wet, wet-dry and dry-wet sand were exposed to a …

Evolutionary Adaptations Of Biofilms Infecting Cystic Fibrosis Lungs Promote Mechanical Toughness By Adjusting Polysaccharide Production, Kristin Kovach, Megan Davis-Fields, Yasuhiko Irie, Kanishk Jain, Shashvat Doorwar, Katherine Vuong, Numa Dhamani, Kishore Mohanty, Ahmed Touhami, Vernita D. Gordon

Biology Faculty Publications

Biofilms are communities of microbes embedded in a matrix of extracellular polymeric substances, largely polysaccharides. Multiple types of extracellular polymeric substances can be produced by a single bacterial strain. The distinct polymer components of biofilms are known to provide chemical protection, but little is known about how distinct extracellular polysaccharides may also protect biofilms against mechanical stresses such as shear or phagocytic engulfment. Decades-long infections of Pseudomonas. aeruginosa biofilms in the lungs of cystic fibrosis patients are natural models for studies of biofilm fitness under pressure from antibiotics and the immune system. In cystic fibrosis infections, production of the extracellular …

Oviposition Traits Generate Extrinsic Postzygotic Isolation Between Two Pine Sawfly Species, Emily E. Bendall, Kim L. Vertacnik, Catherine R. Linnen

Biology Faculty Publications

Background: Although empirical data indicate that ecological speciation is prevalent in nature, the relative importance of different forms of reproductive isolation and the traits generating reproductive isolation remain unclear. To address these questions, we examined a pair of ecologically divergent pine-sawfly species: while Neodiprion pinetum specializes on a thin-needled pine (Pinus strobus), N. lecontei utilizes thicker-needled pines. We hypothesized that extrinsic postzygotic isolation is generated by oviposition traits. To test this hypothesis, we assayed ovipositor morphology, oviposition behavior, and host-dependent oviposition success in both species and in F1 and backcross females.

Results: Compared to N. lecontei, N. …

Effect Of Seed Morph And Light Level On Growth And Reproduction Of The Amphicarpic Plant Amphicarpaea Edgeworthii (Fabaceae), Keliang Zhang, Jerry M. Baskin, Carol C. Baskin, Xuejun Yang, Zhenying Huang

Biology Faculty Publications

Amphicarpic plants produce aerial and subterranean fruits on an individual plant, and these heteromorphic diaspores give rise to plants that differ in growth and ecology. Amphicarpaea edgeworthii is a summer annual amphicarpic species that grows over a range of light levels. We aimed to compare the response to shading intensity of plants of A. edgeworthii grown throughout their life cycle from aerial seeds (ASP) and from subterranean seeds (SSP). We hypothesized that vegetative and reproductive growth of plants from ASP and SSP respond differently to light. Plants were grown from ASP and SSP under 0, 46, 71 and 90% shading …

Hosts, Nesting Behavior, And Ecology Of Some North American Spider Wasps (Hymenoptera: Pompilidae), Ii, Frank E. Kurczewski, Glavis B. Edwards, James P. Pitts

Biology Faculty Publications

This monograph is a continuation of a multiyear study of the genera and species of North American spider wasps (Pompilidae) and their spider host families, genera and species, nesting behavior, ecology, and natural communities. The study enlarges and enhances host preference, nesting behavior, and ecological information for 77 North American pompilid taxa. The first North American Pompilidae records for the families Tengellidae and Segestriidae, both from central coastal California, are reported herein. New host spider genera and species are listed for many of the pompilid species, including the first North American host record for Dipogon (Dipogon) g. graenicheri …

Comparative Postembryonic Skeletal Ontogeny In Two Sister Lineages Of Old World Tree Frogs (Rhacophoridae: Taruga, Polypedates), Gayani Senevirathne, Ryan R. Kerney, Madhava Meegaskumbura

Biology Faculty Publications

Rhacophoridae, a family of morphologically cryptic frogs, with many genetically distinct evolutionary lineages, is understudied with respect to skeletal morphology, life history traits and skeletal ontogeny. Here we analyze two species each from two sister lineages, Taruga and Polypedates, and compare their postembryonic skeletal ontogeny, larval chondrocrania and adult osteology in the context of a well-resolved phylogeny. We further compare these ontogenetic traits with the direct-developing Pseudophilautus silus. For each species, we differentially stained a nearly complete developmental series of tadpoles from early postembryonic stages through metamorphosis to determine the intraspecific and interspecific differences of cranial and postcranial …

Patch-Occupancy Survey Of Elephant (Loxodonta Africana) Surrounding Livingstone, Zambia, David Youldon, Jackie Abell, Joanne Briffitt, Bruce A. Schulte

Biology Faculty Publications

Wild elephants represent the biggest human–wildlife conflict issue in Livingstone, Zambia. However, little is known about their movements. This survey investigated elephants’ habitat use outside a core protected and fenced zone that forms part of Mosi-oa-Tunya National Park, Zambia. Using ‘patch-occupancy’ methodology, indications of elephant presence (feeding behaviour, dung and tracks) were surveyed. The survey aimed to assist proposed future monitoring exercises by defining the geographical extent that should be considered to improve accuracy in species abundance estimates. Results were supplemented using collected indications of elephant presence from prior monitoring exercises, and during this survey. Elephant presence was confirmed up …

A Spanner In The Works: Human–Elephant Conflict Complicates The Food–Water–Energy Nexus In Drylands Of Africa, Bruce Schulte, Mwangi Githiru, Urbanus Mutwiwa, Simon Kasaine

Biology Faculty Publications

The two major conservation issues for drylands of Africa are habitat loss or degradation and habitat fragmentation, largely fromagriculture, charcoal production, and infrastructural development. A key question for management is how these landscapes can retain their critical ecological functions and services, while simultaneously supporting resilient livelihoods. It is a clear nexus question involving food (agriculture), water, and energy (fuelwood), which is complicated by human–wildlife conflicts. While these could appear disparate issues, they are closely connected in dryland forest landscapes of Africa where elephants occur close to areas of human habitation. For instance, crop failure, whether due to weather or wildlife …

Probing For Binding Regions Of The Ftsz Protein Surface Through Site-Directed Insertions: Discovery Of Fully Functional Ftsz-Fluorescent Proteins, Desmond A. Moore, Zakiya N. Whatley, Chandra P. Joshi, Masaki Osawa, Harold P. Erickson

Biology Faculty Publications

FtsZ, a bacterial tubulin homologue, is a cytoskeletal protein that assembles into protofilaments that are one subunit thick. These protofilaments assemble further to form a “Z ring” at the center of prokaryotic cells. The Z ring generates a constriction force on the inner membrane and also serves as a scaffold to recruit cell wall remodeling proteins for complete cell division in vivo. One model of the Z ring proposes that protofilaments associate via lateral bonds to form ribbons; however, lateral bonds are still only hypothetical. To explore potential lateral bonding sites, we probed the surface of Escherichia coli FtsZ …

Real-Time Quantitative Pcr To Demonstrate Gene Expression In An Undergraduate Lab, Abijeet Singh Mehta, Amit Singh

Biology Faculty Publications

The objective of this teaching note is to develop a laboratory exercise, which allows students to get a hands-on experience of a molecular biology technique to analyze gene expression. The short duration of the biology laboratory for an undergraduate curriculum is the biggest challenge with the development of new labs. An important part of cell biology or molecular biology undergraduate curriculum is to study gene expression. There are many labs to study gene expression in qualitative manner. The commonly used reporter gene expression studies are primarily qualitative. However, there is no hands-on experience exercise to quantitatively determine gene expression. Therefore, …

How Do Former Undergraduate Mentors Evaluate Their Mentoring Experience 3-Years Post-Mentoring: A Phenomenological Study, Kari L. Nelson, Christine E. Cutucache

Biology Faculty Publications

This phenomenological study involves a unique, longitudinal assessment of the lived experiences of former undergraduate mentors (n=7) in light of their current experiences (i.e., career or advanced schooling). The objective of a phenomenological study is to engage in in-depth probing of a representative number of participants. Specifically, we followed up with graduates of the Nebraska STEM 4U (NE STEM 4U) intervention 3 years post-program, with the overall goal of describing the mentors’ experiences using the lens of their current experiences. This type of longitudinal perspective of mentoring is greatly lacking in the current literature. At the time of the interviews, …

Sharp-Tailed Grouse Nest Survival And Nest Predator Habitat Use In North Dakota’S Bakken Oil Field, Paul C. Burr, Aaron C. Robinson, Randy T. Larsen, Robert A. Newman, Susan N. Ellis-Felege

Biology Faculty Publications

Recent advancements in extraction technologies have resulted in rapid increases of gas and oil development across the United States and specifically in western North Dakota. This expansion of energy development has unknown influences on local wildlife populations and the ecological interactions within and among species. Our objectives for this study were to evaluate nest success and nest predator dynamics of sharp-tailed grouse (Tympanuchus phasianellus) in two study sites that represented areas of high and low energy development intensities in North Dakota. During the summers of 2012 and 2013, we monitored 163 grouse nests using radio telemetry. Of these, …

Increased Bufflehead (Bucephala Albeola) Breeding Activity In Minnesota, Susan N. Ellis-Felege, Cassandra G. Skaggs, Gregory A. Knutsen

Biology Faculty Publications

Buffleheads (Bucephala albeola) predominantly nest in the boreal forests and aspen parklands of Canada and Alaska. Historically, Buffleheads were common migrants but not summer residents in Minnesota. However, recent observations in Minnesota and surrounding states suggest increased breeding activity in the region. In 1978, the first Bufflehead brood in Minnesota was recorded at East Park Wildlife Management Area. Annually, Agassiz National Wildlife Refuge (NWR) has conducted pair and brood surveys, with species-specific records available from 1990 to 2014. We report an increase in numbers of Bufflehead breeding pairs and broods at Agassiz NWR and new pair observations in …

Landscape Features Affecting Northern Bobwhite Predator-Specific Nest Failures In Southeastern Usa, Susan N. Ellis-Felege, Shannon E. Albeke, Nathan P. Nibbelink, Michael J. Conroy, Clay Sisson, William E. Palmer, John P. Carroll

Biology Faculty Publications

Nest predation is a critical component in avian productivity and typically is the leading cause of nest failure for most birds. Several landscape features are thought to drive the behavioral interaction between northern bobwhite (Colinus virginianus; e.g., nest placement) and their predators (e.g., search methods for food acquisition). In order to understand habitat characteristics influencing predation, we studied bobwhite nests using 24-hour near-infrared video cameras. We monitored 675 bobwhite nests with cameras on 3 properties in northern Florida and southern Georgia, USA, during 2000–2006. To test the association between nest failures and specific failure causes with landscape structure, we calculated …

Effect Of Human Cytomegalovirus (Hcmv) Us27 On Cxcr4 Receptor Internalization Measured By Fluorogen-Activating Protein (Fap) Biosensors, J. M. Boeck, Juliet Spencer

Biology Faculty Publications

Human cytomegalovirus (HCMV) is a widespread pathogen and a member of the Herpesviridae family. HCMV has a large genome that encodes many genes that are non-essential for virus replication but instead play roles in manipulation of the host immune environment. One of these is the US27 gene, which encodes a protein with homology to the chemokine receptor family of G protein-coupled receptors (GPCRs). The US27 protein has no known chemokine ligands but can modulate the signaling activity of host receptor CXCR4. We investigated the mechanism for enhanced CXCR4 signaling in the presence of US27 using a novel biosensor system comprised …

Human Cytomegalovirus Interleukin-10 Enhances Matrigel Invasion Of Mda-Mb-231 Breast Cancer Cells, Cendy Valle Oseguera, Juliet Spencer

Biology Faculty Publications

Background: While some risk factors for breast cancer are well-known, the influence of other factors, particularly virus infection, remains unclear. Human cytomegalovirus (HCMV) is widespread in the general population, and both molecular and epidemiological evidence has indicated links between HCMV and breast cancer. The HCMV protein cmvIL-10 is a potent suppressor of immune function that has also been shown to promote proliferation and migration of breast cancer cells. In this study, the impact of cmvIL-10 on tumor cell invasion through a simulated basement membrane was investigated.

Results: MDA-MB-231 breast cancer cells exhibited invasion through a matrigel layer that was significantly …

Detection Of Intestinal Pathogens In River, Shore, And Drinking Water In Lima, Peru, David Grothen, Sydney J. Zach, Paul H. Davis

Biology Faculty Publications

Water quality management is an ongoing struggle for many locations worldwide. Current testing of water supplies can be time-consuming, expensive, and lack sensitivity. This study describes an alternative, easy-to-use, and inexpensive method to water sampling and testing at remote locations. This method was employed to detect a number of intestinal pathogens in various locations of Lima, Peru. A total of 34 PCR primer pairs were tested for specificity and high-yield amplification for 12 different pathogens using known DNA templates. Select primers for each pathogen were then tested for minimum detection limits of DNA. Water samples were collected from 22 locations. …

Predicting Hiv Pre-Exposure Prophylaxis Efficacy For Women Using A Preclinical Pharmacokinetic-Pharmacodynamic In Vivo Model, Angela Wahl, Phong T. Ho, Paul W. Denton, Katy L. Garrett, Michael G. Hudgens, Glenn Swartz, Cynthia O'Neill, Fulvia Veronese, Angela D. Kashuba, J. Victor Garcia

Biology Faculty Publications

The efficacy of HIV pre-exposure prophylaxis (PrEP) relies on adherence and may also depend on the route of HIV acquisition. Clinical studies of systemic tenofovir disoproxil fumarate (TDF) PrEP revealed reduced efficacy in women compared to men with similar degrees of adherence. To select the most effective PrEP strategies, preclinical studies are critically needed to establish correlations between drug concentrations (pharmacokinetics [PK]) and protective efficacy (pharmacodynamics [PD]). We utilized an in vivo preclinical model to perform a PK-PD analysis of systemic TDF PrEP for vaginal HIV acquisition. TDF PrEP prevented vaginal HIV acquisition in a dose-dependent manner. PK-PD modeling of …

Fostering Curiosity, Inquiry, And Scientific Thinking In Elementary School Students: Impact Of The Ne Stem 4u Intervention, Heather Leas, Kari L. Nelson, Neal Grandgenett, William E. Tapprich, Christine E. Cutucache

Biology Faculty Publications

In this qualitative study, we assessed the impact of the NE STEM 4U intervention on elementary school youth in terms of excitement, curiosity, and STEM concepts. The NE STEM 4U intervention incorporates a problem-based learning theoretical framework in an after-school time, weekly or twice-weekly intervention. We assessed student performance over two academic years of participation in the intervention using the Dimensions of Success observational tool. Ultimately, we link this mentor-led program with increases in curiosity, inquiry, and STEM concept gains. Taken together, these findings support after-school interventions in STEM areas as key encouraging excitement in youth and motivation to pursue …

Stretch Activated Channels In Proprioceptive Organs Of Crab And Crayfish Are Sensitive To Gadolinium But Not Amiloride, Ruthenium Red Or Low Ph, Viresh Dayaram, Cole A. Malloy, Sarah Martha, Brenda Alvarez, Ikenna Chukwudolue, Nadera Dabbain, Dlovan D.Mahmood, Slavina Goleva, Tori Hickey, Angel Ho, Molly King, Paige Kington, Matthew Mattingly, Samuel Potter, Landon Simpson, Amanda Spence, Henry Uradu, Jacob Van Doorn, Robin L. Cooper

Biology Faculty Publications

The type of stretch activated receptors (SARs) in the chordotonal organs in the crab walking leg and of the muscle receptor organ (MRO) in the crayfish abdomen have not yet been classified as to their molecular or pharmacological profile. The purpose of this study is to examine the pharmacological profile of SARs in the proprioceptive neurons in the crab and crayfish models. Since many SARs share the pharmacological profile of displaying low pH or being proton sensitive (i.e. being more active) or blocked by the diuretic amiloride or ruthenium red as well as being blocked by the broad stretch activated …

Quorum Quenching Activity Of Lysates From Bioluminescent Bacteria Isolated From Selected Philippine Marine And Freshwater Organisms, Janice A. Ragaza, Roja G. Angeles-Gumban, Mudjekeewis D. Santos, Minerva Fatimae H. Ventolero, Ronie J. Calugay

Biology Faculty Publications

Pathogens use cell density dependent gene expression known as Quorum Sensing (QS) to launch virulent factors. Targeting the QS circuit without killing the pathogens is a very promising alternative to using antibiotics which generate antibiotic resistance. The identity and diversity of bioluminescent bacteria associated with Philippine aquatic organisms, and their potential as sources of anti-QS or quorum quenching (QQ) molecules remain unknown. In this study, out of 43 organisms, 30 were observed to harbor bioluminescent bacteria with 26 from marine and four from freshwater sources. Purified bioluminescent bacterial cultures were screened for QQ activity using motility assay and the membrane …

An Undergraduate Cell Biology Lab: Western Blotting To Detect Proteins From Drosophila Eye, Neha Gogia, Ankita Sarkar, Amit Singh

Biology Faculty Publications

We have developed an undergraduate laboratory to allow detection and localization of proteins in the compound eye of Drosophila melanogaster, a.k.a fruit fly. This lab was a part of the undergraduate curriculum of the cell biology laboratory course aimed to demonstrate the use of Western Blotting technique to study protein localization in the adult eye of Drosophila. Western blotting, a two-day laboratory exercise, can be used to detect the presence of proteins of interests from total protein isolated from a tissue. The first day involves isolation of proteins from the tissue and SDS-PAGE (sodium dodecyl sulfate-polyacrylamide) gel …

Dynamic Acquisition And Loss Of Dual-Obligate Symbionts In The Plant-Sap-Feeding Adelgidae (Hemiptera: Sternorrhyncha: Aphidoidea), Carol D. Von Dohlen, Usha Spaulding, Kistie B. Patch, Ethan P. White, Robert G. Foottit, Nathan P. Havill, Gaelen R. Burke

Biology Faculty Publications

Sap-sucking insects typically engage in obligate relationships with symbiotic bacteria that play nutritional roles in synthesizing nutrients unavailable or in scarce supply from the plant-sap diets of their hosts. Adelgids are sap-sucking insects with complex life cycles that involve alternation between conifer tree species. While all adelgid species feed on spruce during the sexual phase of their life cycle, each adelgid species belongs to a major lineage that feeds on a distinct genus of conifers as their alternate host. Previous work on adelgid symbionts had discovered pairs of symbionts within each host species, and unusual diversity across the insect family, …

A Computational Study Of Vegf Production By Patterned Retinal Epithelial Cell Colonies As A Model For Neovascular Macular Degeneration, Qanita Bani Baker, Gregory J. Podgorski, Elizabeth Vargis, Nicholas Flann

Biology Faculty Publications

Background: The configuration of necrotic areas within the retinal pigmented epithelium is an important element in the progression of age-related macular degeneration (AMD). In the exudative (wet) and non-exudative (dry) forms of the disease, retinal pigment epithelial (RPE) cells respond to adjacent atrophied regions by secreting vascular endothelial growth factor (VEGF) that in turn recruits new blood vessels which lead to a further reduction in retinal function and vision. In vitro models exist for studying VEGF expression in wet AMD (Vargis et al., Biomaterials 35(13):3999–4004, 2014), but are limited in the patterns of necrotic and intact RPE epithelium they can …

Analysis Of The Oil Biosynthesis Transcripts Of The Moringa Oleifera Lam. Mature Seed Embryos Using Rna Sequencing, Vivian A. Panes, A Kitazumi, M Butler, R.D Baoas, B.G De Los Reyes

Biology Faculty Publications

Moringa oleifera seeds are capable of producing 40% edible oils that are gaining significance due to its nutritional advantages. Several studies have examined M. oleifera seed oil, nevertheless, these studies focused on the extraction of oil and methods of biodiesel production. There is a paucity of information on transcriptome level studies to determine the unigenes involved in oil biosynthesis metabolic pathways. The main objective of this study is to explore the transcriptome of the mature embryo of M. oleifera Lam. particularly the key genes related to oil biosynthesis. The transcriptome reflects the set of genes that are actively expressed at …

Sepals And Petals And Stamens—Oh, My! Or, A Brief Discourse On Putative Homologies Of Perianth Elements Of Common Black Cohosh, W. John Hayden

Biology Faculty Publications

I encountered some contradictory information while preparing to write the 2017 Wildflower of the Year brochure: some sources describe flowers of Actaea racemosa, Common Black Cohosh, as having petals, while others say petals are absent. How can that be? How could there be such uncertainty about this common plant, one known to science since before the time of Linnaeus? After a little research, I decided to describe Black Cohosh flowers as having a series of organs interpretable either as staminodes (nonfunctional stamens) or as petals located between its sepals and stamens (Figure 1). Frankly, I waffled on the petal issue, …

Actaea Racemosa: The Slender Wands Of Flowering Common Black Cohosh Beckon Us To Explore Woodlands, W. John Hayden

Biology Faculty Publications

Common Black Cohosh is a perennial rhizomatous forest herb. Its horizontal rhizomes bear numerous adventitious roots on the underside and aerial stems of annual duration on the upper side, along with knobby scars left from aerial stems of previous years. Leaves are alternate, twice or thrice compound in ternate or pinnate patterns, and large—up to 1 m long. Individual leaflet size and shape vary with position in the large compound leaves, with position of a leaf on the stem, and from population to population. Most often leaflets are coarsely serrate, lobed to deeply incised, with a truncate to cuneate base …

Identification Of Rifampicin Resistance Mutations In Escherichia Coli, Including An Unusual Deletion Mutation, Eugene Y. Wu, Angela K. Hilliker

Biology Faculty Publications

Rifampicin is an effective antibiotic against mycobacterial and other bacterial infections, but resistance readily emerges in laboratory and clinical settings. We screened Escherichia coli for rifampicin resistance and identified numerous mutations to the gene encoding the β chain of RNA polymerase (rpoB), including an unusual nine nucleotide deletion mutation. Structural modeling of the deletion mutant indicates locations of potential steric clashes with rifampicin. Sequence conservation in the region near the deletion mutation suggests a similar mutation may also confer resistance during the treatment of tuberculosis.

The Hidden History Of Humming Frogs, Rafael O. De Sá

Biology Faculty Publications

In the depths of Brazil’s Atlantic Forest, researchers are battling to identify species before they are lost for good. Dr Rafael O de Sá, Professor of Biology at the University of Richmond, Virginia, USA, specialises in a group known as the ‘narrow-mouthed frogs’ and has already found four species new to science.