Life Sciences Commons^™

Peritrophic Membrane Of The Penaeid Shrimp, Sicyonia Ingentis; Structure, Formation And Permeability., Gary Martin

Gary Martin

Peritrophic membranes (PTMs) are secreted acellular layers that separate ingested materials from the gut epithelium in a variety of invertebrates. In insects and crustaceans, PTMs are produced in the midgut trunk (MGT, or intestine), but the MGT in decapod crustaceans, unlike that of insects, is not involved with digestion or absorption of food. We demonstrate that the PTM in the penaeid shrimp Sicyonia ingentis is similar to that in other crustaceans that have been studied and is primarily composed of chitin. The lectin WGA binds only to the PTM and glycocalyx along the microvilli of the midgut cells, which is …

Physical And Structural Basis For The Strong Interactions Of The -Impy- Central Pairing Motif In The Polyamide F-Impyim, K. Buchmueller, S. Bailey, D. Matthews, Z. Taherbhai, J. Register, Z. Davis, Chrystal Bruce, C. O'Hare, J. Hartley, M. Lee

Chrystal D. Bruce

The polyamide f-ImPyIm has a higher affinity for its cognate DNA than either the parent analogue, distamycin A (10-fold), or the structural isomer, f-PyImIm (250-fold), has for its respective cognate DNA sequence. These findings have led to the formulation of a two-letter polyamide “language” in which the -ImPy- central pairings associate more strongly with Watson−Crick DNA than -PyPy-, -PyIm-, and -ImIm-. Herein, we further characterize f-ImPyIm and f-PyImIm, and we report thermodynamic and structural differences between -ImPy- (f-ImPyIm) and -PyIm- (f-PyImIm) central pairings. DNase I footprinting studies confirmed that f-ImPyIm is a stronger binder than distamycin A and f-PyImIm and …

Cj1121c, A Novel Udp-4-Keto-6-Deoxy-Glcnac C-4 Aminotransferase Essential For Protein Glycosylation And Virulence In Campylobacter Jejuni, Somalinga Vijayakumar, Alexandra Merkx-Jacques, Dinath Ratnayake, Irene Gryski, Ravinder Obhi, Sébastien Houle, Charles M Dozois, Carole Creuzenet

Alexandra Merkx-Jacques

Campylobacter jejuni produces glycoproteins that are essential for virulence. These glycoproteins carry diacetamidobacillosamine (DAB), a sugar that is not found in humans. Hence, the enzymes responsible for DAB synthesis represent potential therapeutic targets. We describe the biochemical characterization of Cj1121c, a putative aminotransferase encoded by the general protein glycosylation locus, to assess its role in DAB biosynthesis. By using overexpressed and affinity-purified enzyme, we demonstrate that Cj1121c has pyridoxal phosphate- and glutamate-dependent UDP-4-keto-6-deoxy-GlcNAc C-4 transaminase activity and produces UDP-4-amino-4,6-dideoxy-GlcNAc. This is consistent with a role in DAB biosynthesis and distinguishes Cj1121c from Cj1294, a homologous UDP-2-acetamido-2,6-dideoxy-beta-l-arabino-4-hexulose C-4 aminotransferase that we …

The Geometry Of The Forisome–Sieve Element–Sieve Plate Complex In The Phloem Of Vicia Faba L. Leaflets, Winfried Peters, Aart Van Bel, Michael Knoblauch

Winfried S. Peters

Forisome Based Biomimetic Smart Materials, Amy Shen, Benjamin Hamlington, Michael Knoblauch, Winfried Peters, William Pickard

Winfried S. Peters

Splenic Endothelial Cell Lines Support Development Of Dendritic Cells From Bone Marrow, Geneviève Despars, Helen O'Neill

Helen O'Neill

Although growth factors are commonly used to generate dendritic cells (DCs) in vitro, the role of the microenvironment necessary for DC development is still poorly understood. The mixed splenic stromal cell population STX3 defines an in vitro microenvironment supportive of DC development. Dissection of cellular components of the STX3 stroma should provide information about a niche for DC development. STX3 was therefore cloned by single-cell sorting, and a panel of 102 splenic stromal cell lines was established. Four representative splenic stromal cell lines that support hematopoiesis from bone marrow are described here in terms of stromal cell type and DC …

Induction Of Temperate Cyanophage As-1 By Heavy Metal - Copper, Lee Lee, Lui Doris, Patricia Platner, Shi-Fang Hsu, Tin-Chun Chu, John Gaynor, Quinn Vega, Bonnie Lustigman

Tin-Chun Chu, Ph.D.

No abstract provided.

Disarming The Paradox Of Sublethal-Plant Defense Against Insects: Trirhabda Virgata Larval Development Time And Leaf Tissue Loss On Solidago Altissima, Warren Abrahamson, M.J. Wise, R.J. Fox

Warren G. Abrahamson, II

No abstract provided.

Pka-Mediated Erk1/2 Inactivation And Hsp70 Gene Expression Following Exercise, C.W. Melling, Matthew Krause, Earl Noble

Jamie Melling

Exercise induces the expression of the cardioprotective protein, Hsp70, through the activation of its transcription factor HSF1. Recently, we reported that administration of a protein kinase A (PKA) inhibitor suppressed exercise-induced hsp70 gene expression, suggesting a role for PKA in the regulation of HSF1 activation in vivo. While the mechanism by which PKA regulates HSF1 is unclear, studies in vitro have reported that HSF1 is phosphorylated on two serine residues by mitogen activated protein kinases (MAPKs); ERK1/2 (ser307) and JNK/SAPK (ser363). As PKA is a regulator of these protein kinases, the current study examined the role of PKA in their …

Fecundity, Reproductive Ecology, And Influence Of Precipitation On Clutch Size In The Western Slimy Salamander (Plethodon Albagula), Joseph Milanovich

Joseph Milanovich

We investigated the reproductive ecology of the western slimy salamander (Plethodon albagula) in an abandoned mine shaft in the Ouachita National Forest of south-central Arkansas. The mine habitat provided an opportunity to observe nesting behavior, quantify reproductive output, and evaluate the influence of precipitation on fecundity for a population of P. albagula that utilize this particular mine shaft to brood and defend egg clutches. We collected reproductive data on 372 clutches between 1982 and 2004. There was no relationship between the number of eggs per egg clutch versus egg size; snout–vent length, body mass, and tail length were not correlated …

First Record Of Macrolabis (Diptera: Cecidomyiidae) In America: A New Inquiline Species From Dasineura Folliculi Galls On Goldenrods, Warren Abrahamson, N. Dorchin, E.R. Scott

Warren G. Abrahamson, II

No abstract provided.

Edaphic Environment, Gall Midges, And Goldenrod Clonal Expansion In A Mid-Successional Old Field, Warren Abrahamson, M.J. Wise, K. Landis

Warren G. Abrahamson, II

No abstract provided.

Endothelial Cell Cortactin Coordinates Icam-1 Clustering And Actin Cytoskeleton Remodeling During Polymorphonuclear Leukocyte Adhesion And Transmigration, Jennifer Kowalski

Jennifer Kowalski

Endothelial cell ICAM-1 interacts with leukocyte beta2 integrins to mediate adhesion and transmit outside-in signals that facilitate leukocyte transmigration. ICAM-1 redistribution and clustering appear necessary for leukocyte transmigration, but the mechanisms controlling ICAM-1 redistribution and clustering have not been identified. We recently reported that Src kinase phosphorylation of endothelial cortactin regulates polymorphonuclear cell (PMN) transmigration. In this study, we tested the hypotheses that the Src family kinase-cortactin pathway mediates association of ICAM-1 with the actin cytoskeleton and that this association is required for ICAM-1 clustering and leukocyte transmigration. Cross-linking ICAM-1 induced cytoskeletal remodeling and a decrease in ICAM-1 lateral mobility, …

Costs And Benefits Of Gregarious Feeding In The Meadow Spittlebug, Philaenus Spumarius, Warren Abrahamson, M.J. Wise, D.L. Kieffer

Warren G. Abrahamson, II

No abstract provided.

Lactobacillus Vaginal Microbiota Of Women Attending A Reproductive Health Care Service In Benin City, Nigeria., Kingsley Anukam, Emmanuel Osazuwa, Ijeoma Ahonkhai, Gregor Reid

Kingsley C Anukam

OBJECTIVE: The objective of this study was to determine whether Lactobacillus species found in African women differ substantially to those of Caucasian decent, described in previous studies. The vaginal microbiota play an important role in female health, and when the naturally dominant lactobacilli are displaced resulting in bacterial vaginosis (BV), the host is more at risk of acquiring sexually transmitted diseases, including HIV. METHODS: Vaginal samples were collected from 241 healthy, pre-menopausal Nigerian women, which were then Gram stained for Nugent scoring. Microbial DNA was extracted, amplified using PCR and Lactobacillus primers, and processed by Denaturing Gradient Gel Electrophoresis (DGGE). …

Post-Fire Canopy Recovery In Two Fire-Adapted Palms, Serenoa Repens And Sabal Etonia (Arecaceae), Warren Abrahamson, C.R. Abrahamson

Warren G. Abrahamson, II

No abstract provided.

From Lilliput To Brobdingnag: Extending Models Of Mycorrhizal Function Across Scales, Veer Chaudhary

V. Bala Chaudhary

Mycorrhizae occur in nearly all terrestrial ecosystems. Resource exchange between host plants and mycorrhizal fungi influences community, ecosystem, and even global patterns and processes. Understanding the mechanisms and consequences of mycorrhizal symbioses across a hierarchy of scales will help predict system responses to environmental change and facilitate the management of these responses for sustainability and productivity. Conceptual and mathematical models have been developed to help understand and predict mycorrhizal functions. These models are most developed for individual- and population-scale processes, but models at community, ecosystem, and global scales are also beginning to emerge. We review seven types of mycorrhizal models …

Ecology Of Marine Fishes : California And Adjacent Waters, Larry Allen, Daniel Pondella, Michael Horn

Daniel Pondella

Fundamental ideas in marine ecology have emerged from the study of marine fishes. This unique, authoritative, and accessible reference, compiled by 35 luminary ecologists, evolutionary biologists, and ichthyologists, provides the first-ever synthesis and interpretation of the large, often daunting, body of information on the ecology of marine fishes. Comprehensive and generously illustrated, this volume focuses on the fauna of the eastern pacific, paying particular attention to the California coast, which is among the most diverse and best studied of all marine ecosystems.

Susceptibility Of Imidacloprid-Resistant Colorado Potato Beetles To Non-Neonicotinoid Insecticides In The Laboratory And Field Trials., Andrei Alyokhin, Galen Dively, Megan Patterson, David Rogers, John Wollam

Andrei Alyokhin

Repeated use of neonicotinoid insecticides has resulted in the first reported cases of Colorado potato beetle (Leptinotarsa decemlineata (Say)) resistance to imidacloprid. In the laboratory we determined susceptibility of the imidacloprid-resistant Colorado potato beetles from a population in Southern Maine to other insecticides currently registered for use on potato. This population was about 30-fold resistant to imidacloprid and could not be effectively controlled by its applications. Control mortality was significantly higher for the imidacloprid-resistant larvae than for the susceptible larvae, suggesting that fitness disadvantages may be associated with the resistance trait. Resistant larvae exhibited significantly less mortality than susceptible larvae …

Investigating The Glycosylation Of Groel And Its Role In The Virulence Of Campylobacter Jejuni, Alexandra Merkx-Jacques, I. Gryski, C. Creuzenet

Alexandra Merkx-Jacques

Campylobacter jejuni is a food-borne human pathogen and a major cause of gastroenteritis, reactive arthritis and neurological disorders. Due to emerging drug resistant strains, new treatments and/or vaccines need to be developed.

Protein glycosylation, or the post-translational modification of proteins by sugar molecules, plays an important role in this bacterium's virulence including affecting cell-host interactions, immunogenicity and pathogenicity. C jejuni harbours numerous proteins glycosylated by a heptasaccharide containing diacetamidobacillosamine. Our laboratory investigates the enzymes required to make this sugar as well as the glycoproteins on which this glycan is found.

Analysis of C jejuni proteins by Western blot suggests that …

Prospective Energy Densities In The Forisome, A New Smart Material, William Pickard, Michael Knoblauch, Winfried Peters, Amy Shen

Winfried S. Peters

Tailor-Made Composite Functions As Tools In Model Choice: The Case Of Sigmoidal Vs Bi-Linear Growth Profiles, Winfried Peters, Tobias Baskin

Winfried S. Peters

Comparison Of Virulence Gene Profiles Between Escherichia Coli Strains Isolated From Healthy And Diarrheic Swine, Mark Wilson, Karl A Bettelheim, X Y Wu, S Driesen, James Chin, Toni Chapman, I Barchia, D Trott

Mark R Wilson

No abstract provided.

The Effect Of Environmental Parameters And Cyanobacterial Blooms On Phytoplankton Dynamics Of A Portuguese Temperate Lake, Daniela De Figueiredo, Ana Reboleira, S. Antunes, N. Abrantes, U. Azeiteiro, F. Gonçalves, M. Pereira

Ana Sofia P.S. Reboleira

The increasing occurrence of cyanobacterial blooms in freshwaters is of great concern due to the ability of many cyanobacteria to produce cyanotoxins. In the present work, the eutrophied Vela Lake (Central Portugal), used for recreational purposes and as a water source for agriculture, was monitored every fortnight between 2000 and 2001. Phytoplankton diversity and densities were measured and correlated to environmental parameters. A seasonal phytoplanktonic succession was observed and it was mainly correlated with conductivity, temperature, total suspended solids and nutrients availability (particularly phosphorus). Diatoms were dominant during winter months (inferior temperatures and higher nutrients availability) followed by green algae …

Recent Advances In Chlorophyll Biosynthesis, David Bollivar

David Bollivar

The importance of chlorophyll (Chl) to the process of photosynthesis is obvious, and there is clear evidence that the regulation of Chl biosynthesis has a significant role in the regulation of assembly of the photosynthetic apparatus. The understanding of Chl biosynthesis has rapidly advanced in recent years. The identification of genetic loci associated with each of the biochemical steps has been accompanied by a greater appreciation of the role of Chl biosynthesis intermediates in intracellular signaling. The purpose of this review is to provide a source of information for all the steps in Chl and bacteriochlorophyll a biosynthesis, with an …