Life Sciences Commons^™

Maturation Requirements For Dendritic Cells In T Cell Stimulation Leading To Tolerance Versus Immunity, Helen O'Neill, Jonathan Tan

Jonathan Tan

The model that dendritic cell (DC) "maturation" describes the change from an immature, antigen-capturing cell to a mature, antigen-presenting cell is well-established. Classification of DCs in terms of function has been problematic previously. It is therefore proposed that mature and not immature DCs are responsible for antigen presentation and stimulation of T cells. Furthermore, DC antigen presentation to T cells can have two outcomes: tolerance or immunity. The particular outcomes appear to be determined by the activation state of the mature DC. DCs can be activated by a range of environmental stimuli or "danger signals". Here, the hypothesis is advanced …

082313333253 Alamat Apotik Jual Obat Tidur / Bius Di Palembang, Toko Afeng Obat Kuat Bogor

toko afeng obat kuat bogor

Modeling The Acquisition Of Social Rank In Crayfish: Winner And Loser Effects And Self-Structuring Properties, Karlo Hock, Robert Huber

Robert Huber

No abstract provided.

Slate-Throated Redstarts (Myioborus Miniatus) Breeding In Maderas Del Carmen, Coahuila, Mexico, John Mccormack

John E. McCormack

The breeding range of the slate-throated redstart (Myioborus miniatus) stretches from South America to Mexico, where it extends northward along the Sierra Madre Oriental to southeastern Coahuila and along the Sierra Madre Occidental to southern Chihuahua and Sonora. We report the discovery of slate-throated redstarts breeding in the Maderas del Carmen mountains in Coahuila. This represents a range extension of approximately 400 km and is, to our knowledge, the northernmost breeding record for this species.

Taxomic Status Atelophryniscus Chrysophorus Mccranie, Wilson And Williams, 1989, (Anura Bufonidae) Inferred From Phylogeny, Edgar Lehr, Jennifer Pramuk

Edgar Lehr

The family Bufonidae is nearly cosmopolitan in distribution and contains 33 genera. The monotypic bufonid genus Atelophryniscus was described relatively recently from Honduras. This taxon was distinguished from Buto on the basis of its unusual gastromyzophorus tadpole. Stream-dwelling gastromyzophorus tadpoles are atypical within Bufonidae and when Atelophryniscus was described, this type of tadpole was unknown among members of the genus Buto. To investigate the phylogenetic placement of this taxon, we analyzed 83 previously published morphological characters for a sampling of Old and New World bufonids and included newly coded data. The data indicate that (1) there are no autapomorphies supporting …

Pfcg2, A Plasmodium Falciparum Protein Peripherally Associated With The Parasitophorous Vacuolar Membrane, Is Expressed In The Period Of Maximum Hemoglobin Uptake And Digestion By Trophozoites, Roland A. Cooper, Janni Papakrivos, Kristen D. Lane, Hisashi Fujioka, Klaus Lingelbach, Thomas E. Wellems

Roland A. Cooper

How Costly Is It For Poor Farmers To Lift Themselves Out Of Subsistence, Laure C. Dutoit, Olivier Cadot, Marcelo Olarreaga

Olivier Cadot

The main objective of this paper is to provide estimates of the cost of moving out of subsistence for Madagascar's farmers. The analysis is based on a simple asset-return model of occupational choice. Estimates suggest that the entry (sunk) cost associated with moving out of subsistence can be quite large---somewhere between 124 and 153 percent of a subsistence farmer's annual production. Our results make it possible to identify farm characteristics likely to generate large gains if moved out of subsistence, yielding useful information for the targeting of trade-adjustment assistance programs.

The Caenorhabditis Elegans Heterochronic Regulator Lin-14 Is A Novel Transcription Factor That Controls The Developmental Timing Of Transcription From The Insulin/Insulin-Like Growth Factor Gene Ins-33 By Direct Dna Binding., Marta Hristova, Darcy Birse, Yang Hong, Victor R. Ambros

Victor R. Ambros

A temporal gradient of the novel nuclear protein LIN-14 specifies the timing and sequence of stage-specific developmental events in Caenorhabditis elegans. The profound effects of lin-14 mutations on worm development suggest that LIN-14 directly or indirectly regulates stage-specific gene expression. We show that LIN-14 can associate with chromatin in vivo and has in vitro DNA binding activity. A bacterially expressed C-terminal domain of LIN-14 was used to select DNA sequences that contain a putative consensus binding site from a pool of randomized double-stranded oligonucleotides. To identify candidates for genes directly regulated by lin-14, we employed DNA microarray hybridization to compare …

Climatic Unpredictability And Parasitism Of Caterpillars: Implications Of Global Warming, John O. Stireman Iii, Lee A. Dyer, D. H. Janzen, M. S. Singer, J. T. Lill, R. J. Marquis, R. E. Ricklefs, G. L. Gentry, W. Hallwachs, P. D. Coley, J. A. Barone, H. F. Greeney, H. Connahs, P. Barbosa, H. C. Morais, I. R. Diniz

Robert Marquis

Developmental Biology. Encountering Micrornas In Cell Fate Signaling., Xantha Karp, Victor Ambros

Victor R. Ambros

Comment on: LIN-12/Notch activation leads to microRNA-mediated down-regulation of Vav in C. elegans. [Science. 2005]

The Three Dimensional Detection Of Microvasculatory Bed In The Brain Of White Rat Rattus Norvegicus By A Ca2+ -Atpase Method., Amaiak Chilingaryan, Amayak Chilingaryan, Gary Martin

Gary Martin

A procedure is described which allows for the selective and non-injectional staining of the three-dimensional microvasculatory bed (MVB) in thick sections (60–140 μm) of formalin-fixed brain tissue of white rats Rattus norvegicus. This histochemical method detects ATPase activity and takes place between pH 10.5 and 11.2. Calcium ion is used to capture inorganic phosphate, calcium phosphate is converted to lead phosphate, and subsequently converted to black or dark brown lead sulfide. All vessels are revealed due to a precipitate on the endothelium and smooth muscle cells of arterioles. In some vessels, red blood cells also stain. The background is transparent …

Silencing Of Retrotransposons In Dictyostelium By Dna Methylation And Rnai., Markus Kuhlmann, Branimira E. Borisova, Markus Kaller, Pontus Larsson, Dirk Stach, Jianbo Na, Ludwig Eichinger, Frank Lyko, Victor R. Ambros, Fredrik Soderbom, Christian Hammann, Wolfgang Nellen

Victor R. Ambros

We have identified a DNA methyltransferase of the Dnmt2 family in Dictyostelium that was denominated DnmA. Expression of the dnmA gene is downregulated during the developmental cycle. Overall DNA methylation in Dictyostelium is approximately 0.2% of the cytosine residues, which indicates its restriction to a limited set of genomic loci. Bisulfite sequencing of specific sites revealed that DnmA is responsible for methylation of mostly asymmetric C-residues in the retrotransposons DIRS-1 and Skipper. Disruption of the gene resulted in a loss of methylation and in increased transcription and mobilization of Skipper. Skipper transcription was also upregulated in strains that had genes …

16s Rrna Gene Sequence And Phylogenetic Tree Of Lactobacillus Species From The Vagina Of Healthy Nigerian Women, Kingsley Anukam, Emmanuel Osazuwa, Ijeoma Ahonkhai, Gregor Reid

Kingsley C Anukam

Lactobacilli are ubiquitous in nature and in humans they play a very significant role in the general health maintenance of the host. Identification of Lactobacilli has previously been based on cultutre-dependent methods and recently molecular techniques involving gene sequencing are now the ‘gold standard’. Scarce information exists in Africa on the real identity of Lactobacillus species, albeit phylogenetic distances among the species present in the human vagina. 185 vaginal swabs were collected from healthy premenopausal women (18-48 years). Bacterial DNA was extracted, amplified using PCR, with group specific Lactobacillus primers, and processed by denaturing gradient gel electrophoresis (DGGE). DGGE bands …

Analysis Of Andes Frogs (Phrynopus, Leptodactylidae, Anura) Phylogeny Based On 12s And 16s Mitochondrial Rdna Sequences, Edgar Lehr, Guido Fritzsche, Anke Muller

Edgar Lehr

South American leptodactylid frogs of the genus Phrynopus occur in cloud-forest, páramo, subpáramo and puna habitats (1000–4400 m elevation) from Colombia to Bolivia. Currently, there are 34 described species; however, many additional species new to science have been reported from Colombia, Peru, and Bolivia. The phylogeny of the species-diverse Phrynopus is unknown and the position of the genus within Leptodactylidae is poorly understood. We present the results of a phylogenetic study based on 12S and 16S mitochondrial rDNA. Fifteen species of Phrynopus from Bolivia to Ecuador are included, along with several other genera of Leptodactylidae and representatives of other frog …

Expression Profiling Of Arabidopsis Stigma Tissue Identifies Stigma-Specific Genes, Rob Swanson, T Clark, D Preuss

Rob Swanson

Plants discriminate among pollen grains that land on the stigma surface, providing compatible pollen with the nutrients and signals required to proceed in pollination, and in many species, recognizing and inhibiting foreign pollen adhesion, hydration, germination and invasion. Much of the stigma machinery involved in these processes remains unknown. It is likely that the expression of a stigma-specific gene program confers specialized structural and functional properties. Here we used microarray technology and cDNA subtraction to build a profile of candidate stigma genes that facilitate early pollination events. Of over 24,000 Arabidopsis genes probed, we identified 11,403 genes expressed in stigma …

Spiroplasma Penaei Sp. Nov., Associated With Mortalities In Penaeus Vannamei, Pacific White Shrimp, Linda M. Nunan, Donald V. Lightner, Marietta A. Oduori, Gail E. Gasparich

Gail Gasparich

Spiroplasma Leucomae Sp. Nov., Isolated In Poland From White Satin Moth (Leucoma Salicis L.) Larvae, Marietta A. Oduori, Jerzy J. Lipa, Gail E. Gasparich

Gail Gasparich

Callose (Β-1,3 Glucan) Is Essential For Arabidopsis Pollen Wall Patterning, But Not Tube Growth, Rob Swanson

Rob Swanson

Background: Callose (β-1,3 glucan) separates developing pollen grains, preventing their underlying walls (exine) from fusing. The pollen tubes that transport sperm to female gametes also contain callose, both in their walls as well as in the plugs that segment growing tubes. Mutations in CalS5, one of several Arabidopsis β-1,3 glucan synthases, were previously shown to disrupt callose formation around developing microspores, causing aberrations in exine patterning, degeneration of developing microspores, and pollen sterility. Results: Here, we describe three additional cals5 alleles that similarly alter exine patterns, but instead produce fertile pollen. Moreover, one of these alleles (cals5-3) resulted in the …

Problem Solving: A Foundation For Modeling, Janet Hodder, George Middendorf, D. Ebert-May

George Middendorf

No abstract provided.

Mesodermally Expressed Drosophila Microrna-1 Is Regulated By Twist And Is Required In Muscles During Larval Growth., Nicholas S. Sokol, Victor R. Ambros

Victor R. Ambros

Although hundreds of evolutionarily conserved microRNAs have been discovered, the functions of most remain unknown. Here, we describe the embryonic spatiotemporal expression profile, transcriptional regulation, and loss-of-function phenotype of Drosophila miR-1 (DmiR-1). DmiR-1 RNA is highly expressed throughout the mesoderm of early embryos and subsequently in somatic, visceral, and pharyngeal muscles, and the dorsal vessel. The expression of DmiR-1 is controlled by the Twist and Mef2 transcription factors. DmiR-1KO mutants, generated using ends-in gene targeting, die as small, immobilized second instar larvae with severely deformed musculature. This lethality is rescued when a DmiR-1 transgene is expressed specifically in the mesoderm …

Regulatory Functions Of Phospholipase D And Phosphatidic Acid In Plant Growth, Development, And Stress Responses, Xuemin Wang

Xuemin (Sam) Wang

No abstract provided.

Slip Sliding Away: Load-Dependence Of Velocity Generated By Skeletal Muscle Myosin Molecules In The Laser Trap, Edward P. Debold, Joseph B. Patlak, David M. Warshaw

Edward P. Debold

Skeletal muscle's ability to shorten and lengthen against a load is a fundamental property, presumably reflecting the inherent load-dependence of the myosin molecular motor. Here we report the velocity of a single actin filament translocated by a mini-ensemble of skeletal myosin ∼8 heads under constant loads up to 15 pN in a laser trap assay. Actin filament velocity decreased with increasing load hyberbolically, with unloaded velocity and stall force differing by a factor of 2 with [ATP] (30 vs. 100 μM). Analysis of actin filament movement revealed that forward motion was punctuated with rapid backward 60-nm slips, with the slip …

A New Species Of Bufo (Anura Bufonidae) From Andean Peru, Edgar Lehr, Jennifer Pramuk, Mikael Lundberg

Edgar Lehr

A new species of Bufo tentatively assigned to the Bulo veraguensis group is described from forests near Paucartambo de Pasco, Peru, at elevations of 2600-3000 m in the Cordillera Oriental of central Peru. The new species differs from all known bufonids by having numerous large glands with many keratinous tips on the dorsum, large glands on the tibia and forearm, and two large dorsal glands lying between the parotoids. The new species is most similar to Bufa chavin. Both species are compared to each other and B. veraguensis with respect to external characters and skull osteology. The tadpole and call …

Graduate Colloquium, Borbala Mazzag

Borbala Mazzag

No abstract provided.

Evolutionary Innovation: A Bone-Eating Marine Symbiosis, Shana K. Goffredi, Victoria J. Orphan, Greg W. Rouse, Linda Jahnke, Tsegeria Embaye, Kendra Turk, Ray Lee, Robert C. Vrijenhoek

Shana Goffredi

Symbiotic associations between microbes and invertebrates have resulted in some of the most unusual physiological and morphological adaptations that have evolved in the animal world. We document a new symbiosis between marine polychaetes of the genus Osedax and members of the bacterial group Oceanospirillales, known for heterotrophic degradation of complex organic compounds. These organisms were discovered living on the carcass of a grey whale at 2891 m depth in Monterey Canyon, off the coast of California. The mouthless and gutless worms are unique in their morphological specializations used to obtain nutrition from decomposing mammalian bones. Adult worms possess elaborate posterior …

Androdioecy Inferred In The Clam Shrimp Eulimnadia Agassizii (Spinicaudata : Limnadiidae), Stephen Weeks, Ryan Posagi, Michele Cesari, Franca Scanabissi

Stephen C. Weeks

Androdioecy (mixtures of males and hermaphrodites) is a rare mating system in both the plant and animal kingdoms. Androdioecy has been described in three branchiopod species, and is best known from the clam shrimp Eulimnadia texana Packard. Herein we describe sex ratio, genetic and histological evidence from the clam shrimp Eulimnadia agassizii Packard that suggest androdioecy is also found in this species. The E. agassizii population sampled had all-females, and when these females were isolated and allowed to produce eggs, those eggs yielded 100% female offspring in 15 out of 15 cases. Additionally, the originally isolated females proved to be …

Barriers And Flow As Limiting Factors In The Spread Of An Invasive Crayfish (Procambarus Clarkii) In Southern California Streams, Jacob Kerby, Seth Riley, Lee Kats, Paul Wilson

Lee Kats

Invasive crayfish are a major threat to stream ecosystems, yet research has seldom identified successful ways of preventing their spread. Thirty-two stream sections were surveyed during 2000 and 2001 in the Santa Monica Mountains of southern California to determine the distribution of the invasive crayfish Procambarus clarkii. Streams with large barriers (waterfalls, culverts) often did not have crayfish present upstream of barriers. A mark-recapture study indicated that P. clarkii moved both up and downstream between pools, but that barriers significantly reduced movement between pools. Seasonal high flow velocities likely increase passive movement downstream and reduce movement upstream. Results indicate that …

The Reef Fish Assemblage Of The Outer Los Angeles Federal Breakwater, 2002–2003, John Froeschke, Larry Allen, Daniel Pondella

Daniel Pondella

The conspicuous and cryptic fish assemblage of the Los Angeles Federal Breakwater was assessed from 2002 to 2003. Thirty-five species were observed or collected during the study period. The assemblage of cryptic fishes was composed primarily of a mix of Oregonian and San Diegan, species including snubnose sculpin (Orthonopias triacis), coralline sculpin (Artedius corallinus) and blackeye goby (Rhinogobiops nicholsii). The species composition of conspicuous fishes was approximately equal between taxa from these two provinces. Blacksmith (Chromis punctipinnis), black perch (Embiotoca jacksoni) and kelp bass (Paralabrax clathratus) dominated the assemblage of conspicuous fishes. Species composition reflects the localized cool temperature regime …

Three New Species Of Phyrnopus From Central Peru (Amphibia Anura: Leptodactylidae), Edgar Lehr, Mikael Lundberg, Cesar Aguilar

Edgar Lehr

Three new species of Phrynopus (Anura: Leptodactylidae) are described from cloud forest and puna habitats in central Peruvian Departamento de Pasco between 3600 and 4390 m elevation, the latter is the highest known elevation of the genus. The new species have first finger shorter than second, vomerine teeth absent, and tympanic membrane and tympanic annulus absent, but differ in snout-vent length, skin texture, and coloration. Currently 37 species of Phrynopus are described, 26 (70.3%) of which are endemic to Peru.

Digenic Control Of Colouration In The Two-Spot Gourami Trichogaster Trichopterus Trichopterus, Jack Frankel

Jack Frankel