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Biomimetic Actuators: Where Technology And Cell Biology Merge [Review Article], Michael Knoblauch, Winfried Peters Nov 2004

Biomimetic Actuators: Where Technology And Cell Biology Merge [Review Article], Michael Knoblauch, Winfried Peters

Winfried S. Peters

The structural and functional analysis of biological macromolecules has reached a level of resolution that allows mechanistic interpretations of molecular action, giving rise to the view of enzymes as molecular machines. This machine analogy is not merely metaphorical, as bio-analogous molecular machines actually are being used as motors in the fields of nanotechnology and robotics. As the borderline between molecular cell biology and technology blurs, developments in the engineering and material sciences become increasingly instructive sources of models and concepts for biologists. In this review, we provide a – necessarily selective – summary of recent progress in the usage of …


Photo- And Electropatterning Of Hydrogel-Encapsulated Living Cell Arrays, Dirk Albrecht, Valerie Tsang, Robert Sah, Sangeeta Bhatia Nov 2004

Photo- And Electropatterning Of Hydrogel-Encapsulated Living Cell Arrays, Dirk Albrecht, Valerie Tsang, Robert Sah, Sangeeta Bhatia

Dirk R. Albrecht

Living cells have the potential to serve as sensors, naturally integrating the response to stimuli to generate predictions about cell fate (e.g., differentiation, migration, proliferation, apoptosis). Miniaturized arrays of living cells further offer the capability to interrogate many cells in parallel and thereby enable high-throughput and/or combinatorial assays. However, the interface between living cells and synthetic chip platforms is a critical one wherein the cellular phenotype must be preserved to generate useful signals. While some cell types retain tissue-specific features on a flat (2-D) surface, it has become increasingly apparent that a 3-D physical environment will be required for others. …


Evidence For And Characterization Of Ca2+ Binding To The Catalytic Region Of Arabidopsis Thaliana Phospholipase Dβ, Xuemin Wang Nov 2004

Evidence For And Characterization Of Ca2+ Binding To The Catalytic Region Of Arabidopsis Thaliana Phospholipase Dβ, Xuemin Wang

Xuemin (Sam) Wang

Most types of plant phospholipase D (PLD) require Ca2+ for activity, but how Ca2+ affects PLD activity is not well understood. We reported previously that Ca2+ binds to the regulatory C2 domain that occurs in the N terminus of the Ca2+-requiring PLDs. Using Arabidopsis thaliana PLDβ and C2-deleted PLDβ (PLDβcat), we now show that Ca2+ also interacts with the catalytic regions of PLD. PLDβcat exhibited Ca2+-dependent activity, was much less active, and required a higher level of Ca2+ than the full-length PLDβ. Ca2+ binding of the proteins was stimulated by phospholipids; phosphatidylserine was the most effective among those tested. Scatchard …


Embryonic Expression Of Pre-Initiation Dna Replication Factors In Xenopus Laevis, Brian Walter, Jonathan Henry Oct 2004

Embryonic Expression Of Pre-Initiation Dna Replication Factors In Xenopus Laevis, Brian Walter, Jonathan Henry

Brian Walter

We examined the expression of various DNA replication factors, including: cdc45, the factors of the GINS heterotetramer (Sld5, Psf1, Psf2, Psf3), and PCNA, in Xenopus laevis during embryonic development via whole mount in situ hybridization. For the most part, these factors were expressed in similar patterns, with some subtle variations, throughout development within the anterior CNS, pharyngeal arches, and various placodes. More significant variations were also observed, including expression of only Psf1 and Psf2 in the pronephros and unique Psf2 expression in the somitic mesoderm. Overall, these results suggest that common regulatory mechanisms are involved in the transcriptional deployment of …


Is There An Antipredator Blood-Squirting Defense In The Bull Horned Lizard, Phrynosoma Taurus?, George Middendorf Oct 2004

Is There An Antipredator Blood-Squirting Defense In The Bull Horned Lizard, Phrynosoma Taurus?, George Middendorf

George Middendorf

No abstract provided.


A Spiroplasma Associated With Tremor Disease In The Chinese Mitten Crab (Eriocheir Sinensis), Wen Wang, Bohai Wen, Gail E. Gasparich, Ningning Zhu, Liwen Rong, Jianxiu Chen, Zaikuan Xu Aug 2004

A Spiroplasma Associated With Tremor Disease In The Chinese Mitten Crab (Eriocheir Sinensis), Wen Wang, Bohai Wen, Gail E. Gasparich, Ningning Zhu, Liwen Rong, Jianxiu Chen, Zaikuan Xu

Gail Gasparich

An epidemic of tremor disease has been a serious problem in Chinese mitten crabs, Eriocheir sinensis, in China in recent years. The disease-causing agent was previously considered to be a rickettsia-like organism. Here, analysis of the 16S rRNA gene sequence, light and electron microscopy and cultivation in vitro were used to identify the agent. Sequence analysis of the 16S rRNA gene found it to have 98 % identity with that of Spiroplasma mirum. The agent was able to be passed through membrane filters with pores 220 nm in diameter and could be cultivated by inoculating the yolk sac of embryonated …


Size And Organic Content Of Eggs Of Marine Annelids, And The Underestimation Of Egg Energy Content By Dichromate Oxidation, William Jaeckle, Bruno Pernet Jul 2004

Size And Organic Content Of Eggs Of Marine Annelids, And The Underestimation Of Egg Energy Content By Dichromate Oxidation, William Jaeckle, Bruno Pernet

William Jaeckle

Dichromate oxidation is a simple technique that is often used to estimate the energy content of eggs in studies of marine invertebrate life histories (1). We used this method to measure the energy contents of the eggs of 12 species of marine annelids. In combination with measures of egg ash-free dry weight (AFDW), these data yielded estimates of AFDW-specific energy density that were mostly lower than the average weight-specific energy density of carbohydrates. This seemed unlikely to be correct, as invertebrate eggs typically contain little carbohydrate and instead are composed primarily of energy-dense protein and lipid (1, 2). After validating …


Osedax: Bone-Eating Marine Worms With Dwarf Males, G W. Rouse, Shana K. Goffredi, R C. Vrijenhoek Jul 2004

Osedax: Bone-Eating Marine Worms With Dwarf Males, G W. Rouse, Shana K. Goffredi, R C. Vrijenhoek

Shana Goffredi

We describe a new genus, Osedax, and two new species of annelids with females that consume the bones of dead whales via ramifying roots. Molecular and morphological evidence revealed that Osedax belongs to the Siboglinidae, which includes pogonophoran and vestimentiferan worms from deep-sea vents, seeps, and anoxic basins. Osedax has skewed sex ratios with numerous dwarf (paedomorphic) males that live in the tubes of females. DNA sequences reveal that the two Osedax species diverged about 42 million years ago and currently maintain large populations ranging from 105 to 106 adult females.


Vibrio Parahaemolyticus And V. Harveyi Cause Detachment Of The Epithelium From The Midgut Trunk Of The Penaeid Shrimp, Sicyonia Ingentis., Gary G. Martin, Nicole Rubin, Erica Swanson Jul 2004

Vibrio Parahaemolyticus And V. Harveyi Cause Detachment Of The Epithelium From The Midgut Trunk Of The Penaeid Shrimp, Sicyonia Ingentis., Gary G. Martin, Nicole Rubin, Erica Swanson

Gary Martin

Shrimp Sicyonia ingentis were either injected with Vibrio parahaemolyticus (104 CFU) or V. harveyi (106 CFU) or immersed in ASW containing either species at 105 CFU ml-1. These densities were shown in preliminary experiments to kill approximately half the population by 7 d. On Day 7, surviving shrimp were classified as either diseased or apparently healthy, and their midgut trunks (MGT) were examined by light and electron microscopy. All shrimp immersed in ASW containing either species of Vibrio showed detachment of the epithelium in the MGT. In shrimp injected with either species of Vibrio, epithelial detachment was common in diseased …


Responses Of Kit Foxes (Vulpes Macrotis) To Antipredator Blood-Squirting And Blood Of Texas Horned Lizards (Phrynosoma Cornutum), Wade Sherbrooke, George Middendorf, M E. Douglas Jun 2004

Responses Of Kit Foxes (Vulpes Macrotis) To Antipredator Blood-Squirting And Blood Of Texas Horned Lizards (Phrynosoma Cornutum), Wade Sherbrooke, George Middendorf, M E. Douglas

George Middendorf

Six related studies were conducted with four captive juvenile Kit Foxes (Vulpes macrotis) to test the hypothesis that blood-squirting from eye-socket tissues by Texas Horned Lizards (Phrynosoma cornutum) is a canid antipredator defense. In 16 trials, naive “hungry” foxes killed and ate adult Yarrow's Spiny Lizards (Sceloporus jarrovii; eight of eight trials) slightly more frequently than adult P. cornutum (six of eight trials). Adverse responses by foxes (head shaking) were seen in five of six trials in which Phrynosoma squirted blood. Later these experienced foxes, fed ad libitum, killed and ate mice (eight of eight trials) while largely ignoring P. …


Speciation In The Central American Seaway: The Importance Of Taxon Sampling In The Identification Of Trans-Isthmian Geminate Pairs, Matthew T. Craig, Philip A. Hastings, Daniel J. Pondella Ii May 2004

Speciation In The Central American Seaway: The Importance Of Taxon Sampling In The Identification Of Trans-Isthmian Geminate Pairs, Matthew T. Craig, Philip A. Hastings, Daniel J. Pondella Ii

Daniel Pondella

Aim  To create a molecular phylogenetic hypothesis for the closely related serranid genera Alphestes Bloch and Schneider and Dermatolepis Gill and assess the role of the Panamanian Isthmus in speciation within these reef fishes. Location  Tropical eastern Pacific, Caribbean, and Indian Oceans. Methods  Sequence data from one nuclear (TMO-4C4) and three mitochondrial genes (16S, 12S, and cytochrome b) were used in maximum parsimony and maximum likelihood analyses. Results  Here we show that previously hypothesized trans-isthmian geminate species are not each other's closest living relatives. Species of Alphestes Bloch and Schneider in the eastern Pacific are sister taxa indicating post-closure speciation. …


Food Based Approaches For A Healthy Nutrition In Africa, Mamoudou Hama Dicko May 2004

Food Based Approaches For A Healthy Nutrition In Africa, Mamoudou Hama Dicko

Pr. Mamoudou H. DICKO, PhD

The latest estimates of the FAO demonstrate the problems of the fight against hunger. These problems are manifested by the ever-increasing number of chronically undernourished people worldwide. Their numbers during the 1999-2001 period were estimated at about 840 million of which 798 million live in developing countries. Sub-Saharan Africa alone represented 198 million of those. In this part of Africa the prevalence of undernourishment ranges from 5-34%, causing growth retardation and insufficient weight gain among one third of the children under five years of age and resulting in a mortality of 5-15% among these children. Malnutrition resulting from undernourishment is …


Amebiasis And Comparison Of Microscopy To Elisa Technique In Detection Of Entamoeba Histolytica And Entamoeba Dispar, Clarence Lee Apr 2004

Amebiasis And Comparison Of Microscopy To Elisa Technique In Detection Of Entamoeba Histolytica And Entamoeba Dispar, Clarence Lee

Clarence Lee

The analysis of records of amoebal infection in various hospitals in Kilimanjaro indicated frequent occurrence of amebiasis. The population over the age of five years had higher rate of amoebal infection compared to less than that of a five-year-old population; however, both age groups had similar patterns of amebiasis during January 1999 to June 2001. To investigate misdiagnosis of amebiasis, 226 patients (passive cases) in three hospitals and 616 individuals (active cases) from three different localities in Kilimanjaro were examined. In passive cases, the prevalences of Entamoeba histolytica and Entamoeba dispar were 1% and 7.3%, respectively. Among active cases, 1% …


Forisomes, A Novel Type Of Ca2+-Dependent Contractile Protein Motor [Review Article], Michael Knoblauch, Winfried Peters Apr 2004

Forisomes, A Novel Type Of Ca2+-Dependent Contractile Protein Motor [Review Article], Michael Knoblauch, Winfried Peters

Winfried S. Peters

This paper has no abstract; this is the first paragraph. Motility of cell components in both animal and plant cells is mostly based on the movement of motor proteins along actin filaments or microtubules [Boal, 2002]. The dominance of ATP hydrolysis as the energy source for such movements is so complete, that modern textbooks define “motor proteins” as nucleoside triphosphate-dependent actuators [e.g., Alberts et al., 2002]. In only one known case, a reversible mechanism of cell motility is driven by the interaction of Ca2+ and the responsive protein(s). Some sessile ciliates control the effective length of their stalk by means …


Inheritance Of Trunk Banding In The Tetra (Gymnocorymbus Ternetzi Characidae), Jack Frankel Mar 2004

Inheritance Of Trunk Banding In The Tetra (Gymnocorymbus Ternetzi Characidae), Jack Frankel

Jack Frankel

The tetra (Gymnocorymbus ternetzi) exhibits two phenotypes associated with trunk banding. Fish possess either a smoky-gray coloration with two prominent black vertical bands located directly behind the operculum (black tetra) or a lighter coloration and lack these bands (white skirt tetra). Segregation patterns observed from the progenies of 11 different crosses suggest that the inheritance of these phenotypes is controlled by two autosomal loci acting in a complementary fashion, with dominance at both loci required for the expression of the darker, banded phenotype.


Molecular Profiling: Gene Expression Reveals Discrete Phases Of Lens Induction And Development In Xenopus Laevis, Brian Walter, Yimin Tian, Amy Garlisch, Maria Carinato, Matthew Elkins, Adam Wolfe, Jonathan Schaefer, Kimberly Perry, Jonathan Henry Mar 2004

Molecular Profiling: Gene Expression Reveals Discrete Phases Of Lens Induction And Development In Xenopus Laevis, Brian Walter, Yimin Tian, Amy Garlisch, Maria Carinato, Matthew Elkins, Adam Wolfe, Jonathan Schaefer, Kimberly Perry, Jonathan Henry

Brian Walter

No abstract provided.


Using Math In Cell Biology How Do Calcium Channels Work?, Borbala Mazzag Feb 2004

Using Math In Cell Biology How Do Calcium Channels Work?, Borbala Mazzag

Borbala Mazzag

No abstract provided.


Mer1p Is A Modular Splicing Factor Whose Function Depends On The Conserved U2 Snrnp Protein Snu17p, Marc Spingola, Javier Armisen, Manuel Ares Feb 2004

Mer1p Is A Modular Splicing Factor Whose Function Depends On The Conserved U2 Snrnp Protein Snu17p, Marc Spingola, Javier Armisen, Manuel Ares

Marc Spingola

Mer1p activates the splicing of at least three pre‐mRNAs (AMA1, MER2, MER3) during meiosis in the yeast Saccharomyces cerevisiae. We demonstrate that enhancer recognition by Mer1p is separable from Mer1p splicing activation. The C‐terminal KH‐type RNA‐binding domain of Mer1p recognizes introns that contain the Mer1p splicing enhancer, while the N‐terminal domain interacts with the spliceosome and activates splicing. Prior studies have implicated the U1 snRNP and recognition of the 5′ splice site as key elements in Mer1p‐activated splicing. We provide new evidence that Mer1p may also function at later steps of spliceosome assembly. First, Mer1p can activate splicing of introns …


Ethiopian Soils Harbor Natural Populations Of Rhizobia That Form Symbioses With Common Bean (Phaseolus Vulgaris L.), Serawit Kassa, Desta Beyene, Franklin Ampy, Amha Asseffa, Tadesse Gebremedhin, Peter Van Berkum Jan 2004

Ethiopian Soils Harbor Natural Populations Of Rhizobia That Form Symbioses With Common Bean (Phaseolus Vulgaris L.), Serawit Kassa, Desta Beyene, Franklin Ampy, Amha Asseffa, Tadesse Gebremedhin, Peter Van Berkum

Franklin Ampy

The diversity and taxonomic relationships of 83 bean-nodulating rhizobia indigenous to Ethiopian soils were characterized by PCR-RFLP of the internally transcribed spacer (ITS) region between the 16S and 23S rRNA genes, 16S rRNA gene sequence analysis, multilocus enzyme electrophoresis (MLEE), and amplified fragment-length polymorphism. The isolates fell into 13 distinct genotypes according to PCR-RFLP analysis of the ITS region. Based on MLEE, the majority of these genotypes (70%) was genetically related to the type strain of Rhizobium leguminosarum. However, from analysis of their 16S rRNA genes, the majority was placed with Rhizobium etli. Transfer and recombination of the 16S rRNA …


The Genus Spiroplasma And Its Non-Helical Descendants: Phylogenetic Classification, Correlation With Phenotype And Roots Of The Mycoplasma Mycoides Clade, Gail E. Gasparich, Robert F. Whitcomb, Deborah Dodge, Frank E. French, John Glass, David L. Williamson Jan 2004

The Genus Spiroplasma And Its Non-Helical Descendants: Phylogenetic Classification, Correlation With Phenotype And Roots Of The Mycoplasma Mycoides Clade, Gail E. Gasparich, Robert F. Whitcomb, Deborah Dodge, Frank E. French, John Glass, David L. Williamson

Gail Gasparich

The genus Spiroplasma (helical mollicutes: Bacteria: Firmicutes: Mollicutes: Entomoplasmatales: Spiroplasmataceae) is associated primarily with insects. The Mycoplasma mycoides cluster (sensu Weisburg et al. 1989 and Johansson and Pettersson 2002 ) is a group of mollicutes that includes the type species – Mycoplasma mycoides – of Mycoplasmatales, Mycoplasmataceae and Mycoplasma. This cluster, associated solely with ruminants, contains five other species and subspecies. Earlier phylogenetic reconstructions based on partial 16S rDNA sequences and a limited sample of Spiroplasma and Mycoplasma sequences suggested that the genus Mycoplasma was polyphyletic, as the M. mycoides cluster and the grouping that consisted of the hominis and …


A Long Drink Of Water: How Xylem Changes With Depth, Gretchen North Dec 2003

A Long Drink Of Water: How Xylem Changes With Depth, Gretchen North

Gretchen North

No abstract provided.


Long-Term Trends In Annual Reproductive Output Of The Scrub Hickory: Factors Influencing Variation In Size Of Nut Crop, Warren Abrahamson, J.N. Lane Dec 2003

Long-Term Trends In Annual Reproductive Output Of The Scrub Hickory: Factors Influencing Variation In Size Of Nut Crop, Warren Abrahamson, J.N. Lane

Warren G. Abrahamson, II

No abstract provided.


Aquaporins Account For Variations In Hydraulic Conductance For Metabolically Active Root Regions Of Agave Deserti In Wet, Dry, And Rewetted Soil, Gretchen North, P. Martre, P. Nobel Dec 2003

Aquaporins Account For Variations In Hydraulic Conductance For Metabolically Active Root Regions Of Agave Deserti In Wet, Dry, And Rewetted Soil, Gretchen North, P. Martre, P. Nobel

Gretchen North

The importance of aquaporins for root hydraulic conductance (LP) was investigated along roots of the desert succulent Agave deserti in wet, dry and rewetted soil. Water channel activity was inferred from HgCl2-induced reductions of LP that were reversible by 2-mercaptoethanol. Under wet conditions, HgCl2 reduced LP for the distal root region by 50% and for the root region near the shoot base by 36% but did not affect LP for the mid-root region. For all root regions, LP decreased by 30–60% during 10 d in drying soil and was not further reduced by HgCl2. After soil rewetting, LP increased to …


Human Genetic Variation And Health: New Assessment Approaches Based On Ethnogenetic Layering, Fatimah Linda Collier Jackson Dec 2003

Human Genetic Variation And Health: New Assessment Approaches Based On Ethnogenetic Layering, Fatimah Linda Collier Jackson

Fatimah Linda Collier Jackson

Human genetic variation is often biologically relevant, particularly when it influences (or is influenced by) health outcomes. For example, human genetic variation can modulate disease aetiology as in the case of
homozygous beta sickle gene (βS/βS or sickle cell) pathology. Conversely, health outcomes, such as the frequency and duration of homozygous sickle cell pathology, can change affected group gene frequencies by selectively targeting and culling specific genotypes in a group, such as clinically more severe βS Bantu/βS Bantu versions of the βS gene, thereby changing future patterns of genetic variation in this gene.



Insects Raise Some Galling Questions, Warren G. Abrahamson Ii Dec 2003

Insects Raise Some Galling Questions, Warren G. Abrahamson Ii

Warren G. Abrahamson, II

No abstract provided.


Species Specificity In Pollen-Pistil Interactions, Rob Swanson Dec 2003

Species Specificity In Pollen-Pistil Interactions, Rob Swanson

Rob Swanson

For pollination to succeed, pollen must carry sperm through a variety of different floral tissues to access the ovules within the pistil. The pistil provides everything the pollen requires for success in this endeavor including distinct guidance cues and essential nutrients that allow the pollen tube to traverse enormous distances along a complex path to the unfertilized ovule. Although the pistil is a great facilitator of pollen function, it can also be viewed as an elaborate barrier that shields ovules from access from inappropriate pollen, such as pollen from other species. Each discrete step taken by pollen tubes en route …


Pollen And Stigma Structure And Function: The Role Of Diversity In Pollination, Rob Swanson Dec 2003

Pollen And Stigma Structure And Function: The Role Of Diversity In Pollination, Rob Swanson

Rob Swanson

The ornate surfaces of male and female reproductive cells in flowering plants have long attracted attention for their variety and evolutionary significance. These structures, and the molecules involved in sexual interactions, remain among the most rapidly evolving and diverse characteristics known. As varied as they may be, each element takes part in performing the same functions, protecting pollen and stigma from the environment, delivering and capturing pollen, promoting pollen hydration and germination, allowing the entry of appropriate pollen tubes into the stigma, and guiding the tubes to the ovary (Figure 1 A). In this review, we (1) survey recent discoveries …


Classification And Successional Changes Of Mixed-Oak Forests At The Mohn Mill Area, Pennsylvania, Warren G. Abrahamson Ii, A.C. Gohn Dec 2003

Classification And Successional Changes Of Mixed-Oak Forests At The Mohn Mill Area, Pennsylvania, Warren G. Abrahamson Ii, A.C. Gohn

Warren G. Abrahamson, II

No abstract provided.


Using Gall Wasps On Oaks To Test Broad Ecological Concepts, P.W. Price, Warren G. Abrahamson Ii, M.D. Hunter, G. Melika Dec 2003

Using Gall Wasps On Oaks To Test Broad Ecological Concepts, P.W. Price, Warren G. Abrahamson Ii, M.D. Hunter, G. Melika

Warren G. Abrahamson, II

Planning conservation of insect herbivores requires knowing what needs to be conserved and developing a set of predictor variables that aid management. We conducted a state-wide survey to examine the species richness of gall wasps ( Hymenoptera: Cynipidae) on six oak species dominant in the threatened scrub-oak vegetation in peninsular Florida. Eighty-eight cynipid species were recorded; 23 were new species to Florida (a 35% increase), including 17 species new to science and 6 species newly recorded in the state. The cynipid species represented 68% of cynipids of Florida, on only 24% of oak species sampled. This fauna represents a hotspot …


Recruitment Of The Puf3 Protein To Its Mrna Target For Regulation Of Mrna Decay In Yeast, Wendy Olivas, J. S. Jackson, S. S. Houshmandi, Leban F. Lopez Dec 2003

Recruitment Of The Puf3 Protein To Its Mrna Target For Regulation Of Mrna Decay In Yeast, Wendy Olivas, J. S. Jackson, S. S. Houshmandi, Leban F. Lopez

Wendy Olivas

The Puf family of RNA-binding proteins regulates mRNA translation and decay via interactions with 3' untranslated regions (3' UTRs) of target mRNAs. In yeast, Puf3p binds the 3' UTR of COX17 mRNA and promotes rapid deadenylation and decay. We have investigated the sequences required for Puf3p recruitment to this 3' UTR and have identified two separate binding sites. These sites are specific for Puf3p, as they cannot bind another Puf protein, Puf5p. Both sites use a conserved UGUANAUA sequence, whereas one site contains additional sequences that enhance binding affinity. In vivo, presence of either site partially stimulates COX17 mRNA decay, …