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Articles 1 - 30 of 44
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The Effect Of Dissolved Polyunsaturated Aldehydes On Microzooplankton Growth Rates In The Chesapeake Bay And Atlantic Coastal Waters, Peter J. Lavrentyev, Gayantonia Franze, James J. Pierson, Diane K. Stoecker
The Effect Of Dissolved Polyunsaturated Aldehydes On Microzooplankton Growth Rates In The Chesapeake Bay And Atlantic Coastal Waters, Peter J. Lavrentyev, Gayantonia Franze, James J. Pierson, Diane K. Stoecker
Biology Faculty Research
Allelopathy is wide spread among marine phytoplankton, including diatoms, which can produce cytotoxic secondary metabolites such as polyunsaturated aldehydes (PUA). Most studies on diatom-produced PUA have been dedicated to their inhibitory effects on reproduction and development of marine invertebrates. However, little information exists on their impact on key herbivores in the ocean, microzooplankton. This study examined the effects of dissolved 2E,4E-octadienal and 2E,4E-heptadienal on the growth rates of natural ciliate and dinoflagellate populations in the Chesapeake Bay and the coastal Atlantic waters. The overall effect of PUA on microzooplankton growth was negative, …
Analysis Of Sry Duplications On The Rattus Norvegicus Y-Chromosome, Jeremy W. Prokop, Adam C. Underwood, Monte E. Turner, Nic Miller, Dawn Pietzrak, Sarah Scott, Chris Smith, Amy Milsted
Analysis Of Sry Duplications On The Rattus Norvegicus Y-Chromosome, Jeremy W. Prokop, Adam C. Underwood, Monte E. Turner, Nic Miller, Dawn Pietzrak, Sarah Scott, Chris Smith, Amy Milsted
Biology Faculty Research
Background: Gene copy number variation plays a large role in the evolution of genomes. In Rattus norvegicus and other rodent species, the Y-chromosome has accumulated multiple copies of Sry loci. These copy number variations have been previously linked with changes in phenotype of animal models such as the spontaneously hypertensive rat (SHR). This study characterizes the Y-chromosome in the Sry region of Rattus norvegicus, while addressing functional variations seen in the Sry protein products. Results: Eleven Sry loci have been identified in the SHR with one (nonHMG Sry) containing a frame shift mutation. The nonHMGSry is found and conserved in …
Amino Acid Function And Docking Site Prediction Through Combining Disease Variants, Structure Alignments, Sequence Alignments, And Molecular Dynamics: A Study Of The Hmg Domain, Jeremy W. Prokop, Thomas C. Leeper, Zhong-Hui Duan, Amy Milsted
Amino Acid Function And Docking Site Prediction Through Combining Disease Variants, Structure Alignments, Sequence Alignments, And Molecular Dynamics: A Study Of The Hmg Domain, Jeremy W. Prokop, Thomas C. Leeper, Zhong-Hui Duan, Amy Milsted
Biology Faculty Research
Background: The DNA binding domain of HMG proteins is known to be important in many diseases, with the Sox sub-family of HMG proteins of particular significance. Numerous natural variants in HMG proteins are associated with disease phenotypes. Integrating these natural variants, molecular dynamic simulations of DNA interaction and sequence and structure alignments give detailed molecular knowledge of potential amino acid function such as DNA or protein interaction. Results: A total of 33 amino acids in HMG proteins are known to have natural variants in diseases. Eight of these amino acids are normally conserved in human HMG proteins and 27 are …
Estrogen Receptor-Alpha In The Bed Nucleus Of The Stria Terminalis Regulates Social Affiliation In Male Prairie Voles (Microtus Ochrogaster), Kelly Lei, Bruce S. Cushing, Sergei Musatov, Sonoko Ogawa, Kristin M. Kramer
Estrogen Receptor-Alpha In The Bed Nucleus Of The Stria Terminalis Regulates Social Affiliation In Male Prairie Voles (Microtus Ochrogaster), Kelly Lei, Bruce S. Cushing, Sergei Musatov, Sonoko Ogawa, Kristin M. Kramer
Biology Faculty Research
Estrogen receptor alpha (ER alpha) typically masculinizes male behavior, while low levels of ER alpha in the medial amygdala (MeA) and the bed nucleus of the stria terminalis (BST) are associated with high levels of male prosocial behavior. In the males of the highly social prairie vole (Microtus ochrogaster), increasing ER alpha in the MeA inhibited the expression of spontaneous alloparental behavior and produced a preference for novel females. To test for the effects of increased ER alpha in the BST, a viral vector was used to enhance ER alpha expression in the BST of adult male prairie voles. Following …
Webs In Vitro And In Vivo: Spiders Alter Their Orb-Web Spinning Behavior In The Laboratory, Andrew Sensenig, Ingi Agnarsson, Taylor M. Gondek, Todd A. Blackledge
Webs In Vitro And In Vivo: Spiders Alter Their Orb-Web Spinning Behavior In The Laboratory, Andrew Sensenig, Ingi Agnarsson, Taylor M. Gondek, Todd A. Blackledge
Biology Faculty Research
Many studies of the elegant architectures of orb webs are conducted in controlled laboratory environments that remove environmental variability. The degree to which spider behavior in these circumstances resembles that of spiders in the wild is largely unknown. We compared web architecture and silk investment of furrowed orb weavers Larinioides corium's (Clerck 1757) building webs in laboratory cages and spinning webs on fences in the field and found significant differences. The volume of major ampullate silk in radii was 53% lower in cage webs, primarily because the silk was 50% thinner, but also because spiders tended to spin 14% fewer …
Guided Inquiry Lab Exercises In Development And Oxygen Consumption Using Zebrafish, Brian Bagatto
Guided Inquiry Lab Exercises In Development And Oxygen Consumption Using Zebrafish, Brian Bagatto
Biology Faculty Research
Zebrafish have become a model organism in many areas of research and are now being used with more frequency in the classroom to teach important biological concepts. The two guided inquiry exercises in this article are each aimed at a different level of instruction, but each can be modified to fit the needs of many high school or college-level courses. The "Zebrafish Development and Environment'' exercise teaches high school students about zebrafish development by presenting a series of embryos at different ages. Without access to visual references, students are asked to rank developing zebrafish by age and explain their choices. …
Effects Of Microzooplankton Growth And Trophic Interactions On Herbivory In Coastal And Offshore Environments, Matthew R. First, Harlan L. Miller Iii, Peter J. Lavrentyev, James L. Pinckney, Adrian B. Burd
Effects Of Microzooplankton Growth And Trophic Interactions On Herbivory In Coastal And Offshore Environments, Matthew R. First, Harlan L. Miller Iii, Peter J. Lavrentyev, James L. Pinckney, Adrian B. Burd
Biology Faculty Research
We performed serial dilution experiments to estimate rates of gross phytoplankton growth (L) and grazing mortality (m) in both eutrophic (Corpus Christi Bay, Texas, USA) and oligotrophic (offshore Gulf of Mexico) waters. Two parallel experiments were performed in both environments, with seawater pre-screened through 153 or 25 Inn mesh to observe the responses of microzooplankton (MZP) to dilution treatments. MZP biomass changed over the duration of the experimental incubations; in several treatments, MZP net growth rates were >1 d(-1). Patterns of growth varied between dilutions and initial screening size. In the eutrophic system, the ratio of phytoplankton grazing mortality rate …
Avian Incubation Inhibits Growth And Diversification Of Bacterial Assemblages On Eggs, Matthew D. Shawkey, Mary K. Firestone, Eoin L. Brodie, Steven R. Beissinger
Avian Incubation Inhibits Growth And Diversification Of Bacterial Assemblages On Eggs, Matthew D. Shawkey, Mary K. Firestone, Eoin L. Brodie, Steven R. Beissinger
Biology Faculty Research
Microbial infection is a critical source of mortality for early life stages of oviparous vertebrates, but parental defenses against infection are less well known. Avian incubation has been hypothesized to reduce the risk of trans-shell infection by limiting microbial growth of pathogenic bacteria on eggshells, while enhancing growth of commensal or beneficial bacteria that inhibit or competitively exclude pathogens. We tested this hypothesis by comparing bacterial assemblages on naturally incubated and experimentally unincubated eggs at laying and late incubation using a universal 16S rRNA microarray containing probes for over 8000 bacterial taxa. Before treatment, bacterial assemblages on individual eggs from …
Which Sry Locus Is The Hypertensive Y Chromosome Locus?, Monte E. Turner, Joel Farkas, Jeff Dunmire, Daniel Ely, Amy Milsted
Which Sry Locus Is The Hypertensive Y Chromosome Locus?, Monte E. Turner, Joel Farkas, Jeff Dunmire, Daniel Ely, Amy Milsted
Biology Faculty Research
The Y chromosome of the spontaneously hypertensive rat (SHR) contains a genetic component that raises blood pressure compared with the Wistar-Kyoto (WKY) Y chromosome. This research tests the Sry gene complex as the hypertensive component of the SHR Y chromosome. The Sry loci were sequenced in 1 strain with a hypertensive Y chromosome (SHR/Akr) and 2 strains with a normotensive Y chromosome (SHR/Crl and WKY/Akr). Both SHR strains have 7 Sry loci, whereas the WKY strain has 6. The 6 loci in common between SHR and WKY strains were identical in the sequence compared (coding region, 392-bp 5' prime flanking, …
Can Males Successfully Invade Hermaphroditic Populations Of Clam Shrimp (Eulimnadia Texana)?, Stephen C. Weeks
Can Males Successfully Invade Hermaphroditic Populations Of Clam Shrimp (Eulimnadia Texana)?, Stephen C. Weeks
Biology Faculty Research
Androdioecy (mixtures of males and hermaphrodites) is distinguished by its rarity, being found in only similar to 40 animal species. Many of these species are clam shrimp in the genus Eulimnadia. A metapopulation model for the maintenance of androdioecy is tested herein by examining male success in aquaria with a single male-producing hermaphrodite introduced into an otherwise all-hermaphrodite population. This migration experiment did allow males to persist in these populations for seven generations, although at levels below those found in other populations of these shrimp. These results suggest that the maintenance of androdioecy via 'reproductive assurance' is unlikely by way …
Inbreeding Effects On Sperm Production In Clam Shrimp (Eulimnadia Texana), Stephen C. Weeks, Sadie K. Reed, Donald W. Ott, Franca Scanabissi
Inbreeding Effects On Sperm Production In Clam Shrimp (Eulimnadia Texana), Stephen C. Weeks, Sadie K. Reed, Donald W. Ott, Franca Scanabissi
Biology Faculty Research
Hypothesis: Inbreeding depression is manifest in lower sperm production. Organism: Freshwater crustaceans (clam shrimp - Eulimnadia texana), from the southwestern United States, which have high levels of inbreeding. Methods: Comparisons of semi-thin sections of the male gonad among selfed and outcrossed siblings from four families. Results: There was a twofold reduction in sperm production in inbred relative to outcrossed males. Inbreeding depression in males was higher than previous estimates from hermaphrodites. Conclusions: Inbreeding markedly reduces sperm production. The observed low levels of sperm production can explain both the low average outcrossing rates as well as the variation in these rates …
Estrogen Receptors In The Medial Amygdala Inhibit The Expression Of Male Prosocial Behavior, Bruce S. Cushing, Adam Perry, Sergei Musatov, Sonoko Ogawa
Estrogen Receptors In The Medial Amygdala Inhibit The Expression Of Male Prosocial Behavior, Bruce S. Cushing, Adam Perry, Sergei Musatov, Sonoko Ogawa
Biology Faculty Research
Studies using estrogen receptor alpha(ER) knock-out mice indicate that ER alpha masculinizes male behavior. Recent studies of ER alpha and male prosocial behavior have shown an inverse relationship between ER alpha expression in regions of the brain that regulate social behavior, including the medial amygdala (MeA), and the expression of male prosocial behavior. These studies have lead to the hypothesis that low levels of ER alpha are necessary to "permit" the expression of high levels of male prosocial behavior. To test this, viral vectors were used to enhance ER alpha in male prairie voles (Microtus ochrogaster), which display high levels …
Grazing And Virus-Induced Mortality Of Microbial Populations Before And During The Onset Of Annual Hypoxia In Lake Erie, Christopher J. Gobler, Timothy W. Davis, Sarah N. Deonarine, Matthew A. Saxton, Peter J. Lavrentyev, Frank J. Jochem
Grazing And Virus-Induced Mortality Of Microbial Populations Before And During The Onset Of Annual Hypoxia In Lake Erie, Christopher J. Gobler, Timothy W. Davis, Sarah N. Deonarine, Matthew A. Saxton, Peter J. Lavrentyev, Frank J. Jochem
Biology Faculty Research
Lake Erie is the most productive of the North American Great Lakes and experiences annual periods of hypolimnetic hypoxia with unknown consequences for the microbial food web. We established the abundances and mortality rates of microbes in Lake Erie during thermal stratification and determined how they varied with changes in bottom-water dissolved oxygen concentrations. The microbial plankton community (heterotrophic bacteria, Cyanobacteria, eukaryotic phytoplankton, nanozooplankton, microzooplankton) was quantified in surface and bottom waters along with measurements of herbivory and bacterivory rates on eukaryotic and prokaryotic picoplankton and rates of viral lysis of bacteria. High rates of grazing mortality of prokaryotic picoplankton …
Sticky Gecko Feet: The Role Of Temperature And Humidity, Peter H. Niewiarowski, Stephanie Lopez, Liehui Ge, Emily Hagan, Ali Dhinojwala
Sticky Gecko Feet: The Role Of Temperature And Humidity, Peter H. Niewiarowski, Stephanie Lopez, Liehui Ge, Emily Hagan, Ali Dhinojwala
Biology Faculty Research
Gecko adhesion is expected to be temperature insensitive over the range of temperatures typically experienced by geckos. Previous work is limited and equivocal on whether this expectation holds. We tested the temperature dependence of adhesion in Tokay and Day geckos and found that clinging ability at 12 degrees C was nearly double the clinging ability at 32 degrees C. However, rather than confirming a simple temperature effect, our data reveal a complex interaction between temperature and humidity that can drive differences in adhesion by as much as two-fold. Our findings have important implications for inferences about the mechanisms underlying the …
Effects Of Population Size And Density On Pollinator Visitation, Pollinator Behavior, And Pollen Tube Abundance In Lupinus Perennis, Christopher E. Bernhardt, Randall J. Mitchell, Helen J. Michaels
Effects Of Population Size And Density On Pollinator Visitation, Pollinator Behavior, And Pollen Tube Abundance In Lupinus Perennis, Christopher E. Bernhardt, Randall J. Mitchell, Helen J. Michaels
Biology Faculty Research
Both the number and the density of flowering plants in a population can be important determinants of pollinator abundance and behavior. We report the joint effects of population size and density on pollinator visitation and pollination success for Lupinus perennis (Fabaceae). Focusing on five pairs of populations, we matched one small population (125-800 flowering plants) with one distinctly larger population (1000-3000 flowering plants). In these pairs, population size did not affect pollinator communities or pollination success. All measures of pollination success increased significantly with density. Only bee behavior (number of flowers probed per inflorescence) exhibited a significant interaction of size …
Nodal Signaling Is Required For Closure Of The Anterior Neural Tube In Zebrafish, Allisan Aquilina-Beck, Kristine Ilagan, Qin Liu, Jennifer O. Liang
Nodal Signaling Is Required For Closure Of The Anterior Neural Tube In Zebrafish, Allisan Aquilina-Beck, Kristine Ilagan, Qin Liu, Jennifer O. Liang
Biology Faculty Research
Background: Nodals are secreted signaling proteins with many roles in vertebrate development. Here, we identify a new role for Nodal signaling in regulating closure of the rostral neural tube of zebrafish.
The Organizational Effects Of Oxytocin On The Central Expression Of Estrogen Receptor Alpha And Oxytocin In Adulthood, Kristin M. Kramer, Shigeto Yoshida, Eros Papademetriou, Bruce S. Cushing
The Organizational Effects Of Oxytocin On The Central Expression Of Estrogen Receptor Alpha And Oxytocin In Adulthood, Kristin M. Kramer, Shigeto Yoshida, Eros Papademetriou, Bruce S. Cushing
Biology Faculty Research
Background: Previous studies have demonstrated that neonatal manipulation of oxytocin (OT) has effects on the expression of estrogen receptor alpha (ER alpha) and the central production of oxytocin observed in juveniles ( at weaning, 21 days of age). The goal of this study was to determine whether the effects of neonatal manipulation of OT last into adulthood, and if the effects differ from those observed during the early postnatal period. On the first day of life, prairie voles ( Microtus ochrogaster) received one of three doses of OT (High, 3 mu g; Med, 0.3 mu g; Low, 0.03 mu g), …
Genomic And Expression Analysis Of Multiple Sry Loci From A Single Rattus Norvegicus Y Chromosome, Monte E. Turner, Carey Martin, Almir S. Martins, Jeffrey Dunmire, Joel Farkas, Daniel L. Ely, Amy Milsted
Genomic And Expression Analysis Of Multiple Sry Loci From A Single Rattus Norvegicus Y Chromosome, Monte E. Turner, Carey Martin, Almir S. Martins, Jeffrey Dunmire, Joel Farkas, Daniel L. Ely, Amy Milsted
Biology Faculty Research
Background: Sry is a gene known to be essential for testis determination but is also transcribed in adult male tissues. The laboratory rat, Rattus norvegicus, has multiple Y chromosome copies of Sry while most mammals have only a single copy. DNA sequence comparisons with other rodents with multiple Sry copies are inconsistent in divergence patterns and functionality of the multiple copies. To address hypotheses of divergence, gene conversion and functional constraints, we sequenced Sry loci from a single R. norvegicus Y chromosome from the Spontaneously Hypertensive Rat strain (SHR) and analyzed DNA sequences for homology among copies. Next, to determine …
Anatomy Of The Recurrent Coastal Sediment Plume In Lake Michigan And Its Impacts On Light Climate, Nutrients, And Plankton, Henry Vanderploeg, Thomas Johengen, Peter J. Lavrentyev, Changsheng Chen, G. A. Lang, M. A. Agy, M. H. Bundy, J. F. Cavaletto, B. J. Eadie, J. R. Liebig, G. S. Miller, S. A. Ruberg, M. J. Mccormick
Anatomy Of The Recurrent Coastal Sediment Plume In Lake Michigan And Its Impacts On Light Climate, Nutrients, And Plankton, Henry Vanderploeg, Thomas Johengen, Peter J. Lavrentyev, Changsheng Chen, G. A. Lang, M. A. Agy, M. H. Bundy, J. F. Cavaletto, B. J. Eadie, J. R. Liebig, G. S. Miller, S. A. Ruberg, M. J. Mccormick
Biology Faculty Research
As part of the Episodic Events Great Lakes Experiment, we sampled total suspended matter (TSM), light climate, nutrients, and plankton along cross-margin transects in southern Lake Michigan during February, March, and April 1998-2000 to capture conditions before, during, and after the occurrence of storm-driven recurrent coastal sediment plumes to define the anatomy of the resuspension events and get insights into their interactions with nutrients and plankton. Variability in timing and strength of winter storms among years led to different timing, intensity, and extent of plumes among years. TSM concentrations in the core of plumes varied between 15 and 30 mg …
Cadherin2 (N-Cadherin) Plays An Essential Role In Zebrafish Cardiovascular Development, Brian Bagatto, Jessie Francl, Bei Liu, Qin Liu
Cadherin2 (N-Cadherin) Plays An Essential Role In Zebrafish Cardiovascular Development, Brian Bagatto, Jessie Francl, Bei Liu, Qin Liu
Biology Faculty Research
Background: Cadherins are cell surface adhesion molecules that play important roles in development of vertebrate tissues and organs. We studied cadherin2 expression in developing zebrafish heart using in situ hybridization and immunocytochemical methods, and we found that cadherin2 was strongly expressed by the myocardium of the embryonic zebrafish. To gain insight into cadherin2 role in the formation and function of the heart, we analyzed cardiac differentiation and performance in a cadherin2 mutant, glass onion (glo).
A Three-Dimensional Functional Assessment Of Heart And Vessel Development In The Larva Of The Zebrafish (Danio Rerio), Brian Bagatto, Warren Burggren
A Three-Dimensional Functional Assessment Of Heart And Vessel Development In The Larva Of The Zebrafish (Danio Rerio), Brian Bagatto, Warren Burggren
Biology Faculty Research
There has been considerable recent interest in the development of the circulation in the zebrafish. Optical techniques typically used to visualize changes in heart size allow measurement of stroke volume during early vertebrate development, but this approach is complicated in zebrafish larvae because of the heart's irregular shape and its significant change in morphology during the first 6 d of development. By use of a three-dimensional integration of the early zebrafish heart and vessels, we have greatly reduced measurement error of stroke volume and cardiac output and have determined the cross-sectional growth of major vessels in the developing zebrafish larvae. …
Interspecific Competition For Pollination Lowers Seed Production And Outcrossing In Mimulus Ringens, John M. Bell, Jeffrey D. Karron, Randall J. Mitchell
Interspecific Competition For Pollination Lowers Seed Production And Outcrossing In Mimulus Ringens, John M. Bell, Jeffrey D. Karron, Randall J. Mitchell
Biology Faculty Research
Sympatric plant species with similar flowering phenologies and floral morphologies may compete for pollination, and as a consequence potentially influence each other's reproductive success and mating system. Two likely competitors are Mimulus ringens and Lobelia siphilitica, which co-occur in wet meadows of central and eastern North America, produce blue zygomorphic flowers, and share several species of bumble bee pollinators. To test for effects of competition for pollination, we planted experimental arrays of Mimulus ringens, each consisting of genets with unique combinations of homozygous marker genotypes. In two arrays we planted mixtures of Mimulus and Lobelia. and in two additional arrays …
Bergmann's Clines In Ectotherms: Illustrating A Life-History Perspective With Sceloporine Lizards, Michael J. Angilletta Jr., Peter H. Niewiarowski, Arthur E. Dunham, Adam D. Leache, Warren P. Porter
Bergmann's Clines In Ectotherms: Illustrating A Life-History Perspective With Sceloporine Lizards, Michael J. Angilletta Jr., Peter H. Niewiarowski, Arthur E. Dunham, Adam D. Leache, Warren P. Porter
Biology Faculty Research
The generality and causes of Bergmann's rule have been debated vigorously in the last few years, but Bergmann's clines are rarely explained in the context of life-history theory. We used both traditional and phylogenetic comparative analyses to explore the causes of latitudinal and thermal clines in the body size of the eastern fence lizard (Sceloporus undulatus). The proximate mechanism for larger body sizes in colder environments is delayed maturation, which results in a greater fecundity but a lower survival to maturity. Life-history theory predicts that a higher survivorship of juveniles in colder environments can favor the evolution of a Bergmann's …
A Modeling Study Of Benthic Detritus Flux's Impacts On Heterotrophic Processes In Lake Michigan, Changsheng Chen, Lixia Wang, Jianhua Qi, Hedong Liu, Judith Wells Budd, David J. Schwab, Dmitry Beletsky, Henry Vanderploeg, Brian Eadie, Thomas Johengen, James Cotner, Peter J. Lavrentyev
A Modeling Study Of Benthic Detritus Flux's Impacts On Heterotrophic Processes In Lake Michigan, Changsheng Chen, Lixia Wang, Jianhua Qi, Hedong Liu, Judith Wells Budd, David J. Schwab, Dmitry Beletsky, Henry Vanderploeg, Brian Eadie, Thomas Johengen, James Cotner, Peter J. Lavrentyev
Biology Faculty Research
Effects of sediment resuspension-induced benthic detrital flux on the heterotrophic part of the microbial food web in Lake Michigan were examined using a three-dimensional (3-D) coupled biological and physical model. The model was driven by the realistic meteorological forcing observed in March 1999. Wind-induced surface wave dynamics were incorporated into the physical model to generate the bottom flux. The model-generated benthic detrital flux was assumed to be proportional to the difference between model-calculated and critical stresses at the bottom. The model results indicate that detrital flux at the bottom was a key factor causing a significant increase of phosphorus and …
Heritability Of Nectar Traits: Why Do We Know So Little?, Randall J. Mitchell
Heritability Of Nectar Traits: Why Do We Know So Little?, Randall J. Mitchell
Biology Faculty Research
Although floral and extrafloral nectar traits are important for plant reproduction and defense, we know little about their genetic basis. Only a handful of studies have quantified heritable variation for nectar traits, primarily in controlled environments that minimize environmental variation. Most such studies have reported strong genetic influences, with heritabilities often >0.35. However, because nectar traits are often very responsive to environmental variation, even substantial amounts of genetic variation may be swamped out in the,field. Environmental variation deserves to be studied in its own right, including exploration of genotype X environment interaction for nectar traits . Most genetic studies of …
Distribution And Dynamics Of Nitrogen And Microbial Plankton In Southern Lake Michigan During Spring Transition 1999-2000, Wayne S. Gardner, Peter J. Lavrentyev, Joann F. Cavaletto, Mark J. Mccarthy, B. J. Eadie, Thomas Johengen, James Cotner
Distribution And Dynamics Of Nitrogen And Microbial Plankton In Southern Lake Michigan During Spring Transition 1999-2000, Wayne S. Gardner, Peter J. Lavrentyev, Joann F. Cavaletto, Mark J. Mccarthy, B. J. Eadie, Thomas Johengen, James Cotner
Biology Faculty Research
[ 1] Ammonium and amino acid fluxes were examined as indicators of N and microbial food web dynamics in southern Lake Michigan during spring. Either (NH4+)-N-15 or a mixture of N-15-labelled amino acids (both at 4 muM N final concentration) was added to Lake Michigan water. Net fluxes were measured over 24 h under natural light and dark conditions using deck-top incubators and compared to microbial food web characteristics. Isotope dilution experiments showed similar light and dark NH4+ regeneration rates at lake ( 6 versus 5 nM N h(-1)) and river-influenced ( 20 versus 24 nM N h(-1)) sites. Ammonium …
Maintenance Of Androdioecy In The Freshwater Shrimp, Eulimnadia Texana: Field Estimates Of Inbreeding Depression And Relative Male Survival, Stephen C. Weeks, Richard L. Bernhardt
Maintenance Of Androdioecy In The Freshwater Shrimp, Eulimnadia Texana: Field Estimates Of Inbreeding Depression And Relative Male Survival, Stephen C. Weeks, Richard L. Bernhardt
Biology Faculty Research
Androdioecy is a rare form of reproduction, only found in a few plant and animal species, wherein males co-exist with hermaphrodites. This particular form of mixed mating (mixtures of outcrossing and self-fertilization) is predicted to be evolutionarily unstable, with most androdioecious populations thought to be in a transition from hermaphroditism to dioecy, or vice versa. One well-studied androdioecious species is the freshwater clam shrimp Eulimnadia texana. A model by Otto et al. (1993), exploring the stability of this androdioecious system, predicts that males can co-exist with hermaphrodites when males fertilize an average of over twice the number of offspring that …
Cold Acclimation Strategy Is Highly Variable Among The Sunfishes (Centrarchidae), Peter J. Lavrentyev, Deidra R. Tschantz, Elizabeth L. Crockett
Cold Acclimation Strategy Is Highly Variable Among The Sunfishes (Centrarchidae), Peter J. Lavrentyev, Deidra R. Tschantz, Elizabeth L. Crockett
Biology Faculty Research
We tested the hypothesis that the physiological strategy for acclimating to low body temperature is similar among closely related fish. Largemouth bass (Micropterus salmoides), green sunfish (Lepomis cyanellus), bluegill sunfish (Lepomis macrochirus), black crappie (Pomonix nigromaculatus), and white crappie (Pomonix annularis), all members of the family Centrarchidae, were acclimated to 5° and 25°C. Morphometric variables (total mass, total length, organ masses) and enzyme activities (hexokinase; lactate dehydrogenase; and cytochrome oxidase in heart, liver, and muscle) were measured in 5°C- and 25°C-acclimated fish at 5° and 25°C assay temperatures. Each species displayed a distinct physiological response to cold acclimation that differed …
Competition For Pollination Between An Invasive Species (Purple Loosestrife) And A Native Congener, Beverly J. Brown, Randall J. Mitchell, Shirley A. Graham
Competition For Pollination Between An Invasive Species (Purple Loosestrife) And A Native Congener, Beverly J. Brown, Randall J. Mitchell, Shirley A. Graham
Biology Faculty Research
Invasive species are frequently regarded as Superlative competitors that can vegetatively crowd Out natives, but little is known about whether invasives call compete for pollination services with native plants. We hypothesized that, when the showy invasive species Lythrum salicaria (purple loosestrife) was present, pollinator visitation and seed set would be reduced in a native congener, L. alatum (winged loosestrife). To test this hypothesis, we constructed mixed and monospecific plots of the two species. Over two years of study, we found that L. salicaria significantly reduced both pollinator visitation and seed set in L. alatum. Furthermore, pollinators moved frequently between the …
Cold Acclimation Strategy Is Highly Variable Among The Sunfishes (Centrarchidae), Deidra R. Tschantz, Elizabeth L. Crockett, Peter H. Niewiarowski, Richard L. Londraville
Cold Acclimation Strategy Is Highly Variable Among The Sunfishes (Centrarchidae), Deidra R. Tschantz, Elizabeth L. Crockett, Peter H. Niewiarowski, Richard L. Londraville
Biology Faculty Research
We tested the hypothesis that the physiological strategy for acclimating to low body temperature is similar among closely related fish. Largemouth bass (Micropterus salmoides), green sunfish (Lepomis cyanellus), bluegill sunfish (Lepomis macrochirus), black crappie (Pomonix nigromaculatus), and white crappie (Pomonix annularis), all members of the family Centrarchidae, were acclimated to 5degrees and 25degreesC. Morphometric variables (total mass, total length, organ masses) and enzyme activities (hexokinase; lactate dehydrogenase; and cytochrome oxidase in heart, liver, and muscle) were measured in 5degreesC- and 25degreesC- acclimated fish at 5degrees and 25degreesC assay temperatures. Each species displayed a distinct physiological response to cold acclimation that …