Open Access. Powered by Scholars. Published by Universities.®

Life Sciences Commons

Open Access. Powered by Scholars. Published by Universities.®

Articles 1 - 14 of 14

Full-Text Articles in Life Sciences

Genetic Effect Of The Dwarfing Genes On Some Culm Characteristics Associatcd With Lodging Resistance In Bread Wheat, Md. Mahbub Hasan Dec 2009

Genetic Effect Of The Dwarfing Genes On Some Culm Characteristics Associatcd With Lodging Resistance In Bread Wheat, Md. Mahbub Hasan

Md. Mahbub Hasan

Due to the challenge of screening traits related to lodging resistance under natural field conditions, selection for lodging resistant varieties in wheat breeding programs is difficult. The identification of easily measurable culm anatomical traits related to lodging resistance would simplify the selection process. The present study was conducted to determine the effect of dwarfing genes on culm anatomical traits related to lodging resistance in our of basal internode 1. Field and laboratory study was conducted in Shahjalal University of Science and Technology, Sylhet, Bangladesh with eight wheat genotypes having Rhr1, Rht2 dwarfing genes in them and a local land race …


Tracking Insertion Mutants Within Libraries By Deep Sequencing And A Genome-Wide Screen For Haemophilus Genes Required In The Lung, Jeffrey D. Gawronski, Sandy M. S. Wong, Georgia Giannoukos, Doyle V. Ward, Brian J. Akerley Sep 2009

Tracking Insertion Mutants Within Libraries By Deep Sequencing And A Genome-Wide Screen For Haemophilus Genes Required In The Lung, Jeffrey D. Gawronski, Sandy M. S. Wong, Georgia Giannoukos, Doyle V. Ward, Brian J. Akerley

Brian J. Akerley

Rapid genome-wide identification of genes required for infection would expedite studies of bacterial pathogens. We developed genome-scale "negative selection" technology that combines high-density transposon mutagenesis and massively parallel sequencing of transposon/chromosome junctions in a mutant library to identify mutants lost from the library after exposure to a selective condition of interest. This approach was applied to comprehensively identify Haemophilus influenzae genes required to delay bacterial clearance in a murine pulmonary model. Mutations in 136 genes resulted in defects in vivo, and quantitative estimates of fitness generated by this technique were in agreement with independent validation experiments using individual mutant strains. …


Metabolic Variability In Seafloor Brines Revealed By Carbon And Sulphur Dynamics, Samantha B. Joye, Vladimir A. Samarkin, Beth! N. Orcutt, Ian R. Macdonald, Kai-Uwe Hinrichs, Marcus Elvert, Andreas P. Teske, Karen Lloyd, Mark A. Lever, Joseph P. Montoya, Christof D. Meile Apr 2009

Metabolic Variability In Seafloor Brines Revealed By Carbon And Sulphur Dynamics, Samantha B. Joye, Vladimir A. Samarkin, Beth! N. Orcutt, Ian R. Macdonald, Kai-Uwe Hinrichs, Marcus Elvert, Andreas P. Teske, Karen Lloyd, Mark A. Lever, Joseph P. Montoya, Christof D. Meile

Karen Lloyd

Brine fluids that upwell from deep, hot reservoirs below the sea bed supply the sea floor with energy-rich substrates and nutrients that are used by diverse microbial ecosystems. Contemporary hypersaline environments formed by brine seeps may provide insights into the metabolism and distribution of microorganisms on the early Earth or on extraterrestrial bodies. Here we use geochemical and genetic analyses to characterize microbial community composition and metabolism in two seafloor brines in the Gulf of Mexico: an active mud volcano and a quiescent brine pool. Both brine environments are anoxic and hypersaline. However, rates of sulphate reduction and acetate production …


The Generation Of Influenza-Specific Humoral Responses Is Impaired In St6gal I-Deficient Mice., Thandi M. Onami, J Zeng, H. M. Joo, B. Rajini, J. P. Wrammert, M. Y. Sangster Apr 2009

The Generation Of Influenza-Specific Humoral Responses Is Impaired In St6gal I-Deficient Mice., Thandi M. Onami, J Zeng, H. M. Joo, B. Rajini, J. P. Wrammert, M. Y. Sangster

Thandi M. Onami

Posttranslational modification of proteins, such as glycosylation, can impact cell signaling and function. ST6Gal I, a glycosyltransferase expressed by B cells, catalyzes the addition of alpha-2,6 sialic acid to galactose, a modification found on N-linked glycoproteins such as CD22, a negative regulator of B cell activation. We show that SNA lectin, which binds alpha-2,6 sialic acid linked to galactose, shows high binding on plasma blasts and germinal center B cells following viral infection, suggesting ST6Gal I expression remains high on activated B cells in vivo. To understand the relevance of this modification on the antiviral B cell immune response, we …


First Report Of Sweet Wormwood Leaf Blight Disease In India, Kunal Mandal Jan 2009

First Report Of Sweet Wormwood Leaf Blight Disease In India, Kunal Mandal

Kunal Mandal

Artemisia annua is an important drug plant yielding antimalarial compounds. It was found to be infected by Alternaria alternata in India. The pathogen reduces active leaf area and is also known to produce mycotoxins. Hence, the disease demands serious attention to ensure the availability of a safe drug.


The Evolution Of Reduced Microbial Killing, Jan A.C. Vriezen Dr., Michael Valliere, Margaret A. Riley Dr. Jan 2009

The Evolution Of Reduced Microbial Killing, Jan A.C. Vriezen Dr., Michael Valliere, Margaret A. Riley Dr.

Jan A.C. Vriezen Dr.

Bacteria engage in a never-ending arms race in which they compete for limited resources and niche space. The outcome of this intense interaction is the evolution of a powerful arsenal of biological weapons. Perhaps the most studied of these are colicins, plasmid-based toxins produced by and active against Escherichia coli. The present study was designed to explore the molecular responses of a colicin-producing strain during serial transfer evolution. What evolutionary changes occur when colicins are produced with no target present? Can killing ability be maintained in the absence of a target? To address these, and other, questions, colicinogenic strains and …


Effect Of Aqueous Extract Of Aegle Marmelos Fruit On Adherence And Β-Lactam Resistance Of Enteropathogenic Escherichia Coli By Down Regulating Outer Membrane Protein C, Murali Malliga Raman Jan 2009

Effect Of Aqueous Extract Of Aegle Marmelos Fruit On Adherence And Β-Lactam Resistance Of Enteropathogenic Escherichia Coli By Down Regulating Outer Membrane Protein C, Murali Malliga Raman

Murali Malliga Raman

Problem statement: Enteropathogenic Escherichia Coli (EPEC) continue to be a major health problem, leading to death due to diarrhea, predominantly in children below the age of five. Due to evolution of multi drug resistance in EPEC and side effects caused to host by antibiotics necessitated a search for alternative medicines from medicinal plants. One such medicinal plant used since ancient times to cure diarrhea is Aegle marmelos. This study was done to investigate the effect of aqueous extract of Aegle marmelos fruit (AEAM) on outer membrane protein C (OmpC) of EPEC, which plays a key role in adherence and antibiotic …


Actinorhodopsin Genes Discovered Diverse In Freshwater Habitats And Among Cultivated Actinobacteria, A.K. Sharma, K. Sommerfeld, G.S. Bullerjahn, A.R. Matteson, Steven Wilhelm, J. Jezbera, U. Brandt, W.F. Doolittle, M.W. Hahn Jan 2009

Actinorhodopsin Genes Discovered Diverse In Freshwater Habitats And Among Cultivated Actinobacteria, A.K. Sharma, K. Sommerfeld, G.S. Bullerjahn, A.R. Matteson, Steven Wilhelm, J. Jezbera, U. Brandt, W.F. Doolittle, M.W. Hahn

Steven Wilhelm

Microbial rhodopsins are membrane proteins that utilize a retinal chromophore to harvest sunlight for energetic and photosensory functions. Recently, a group of novel rhodopsin sequences named ‘actinorhodopsins’ (ActRs) was hypothesized to exist among uncultured planktonic Actinobacteria. ActRs were discovered by mining metagenomic data obtained during the Venter Institute’s Global Ocean Sampling expedition, from a hypersaline lagoon, two estuaries and a freshwater lake. On the basis of these findings, and many studies that show Actinobacteria are common inhabitants of lakes, we predicted that ActR genes would likely be present in other freshwater habitats and among the genomes of cultivated Actinobacteria …


Identifying The Source Of Unknown Microcystin Genes And Predicting Microcystin Variants By Comparing Genes Within Uncultured Cyanobacterial Cells, C.J. Allender, G.R. Lecleir, J.M. Rinta-Kanto, R.L. Small, M.F. Satchwell, G.L. Boyer, Steven Wilhelm Jan 2009

Identifying The Source Of Unknown Microcystin Genes And Predicting Microcystin Variants By Comparing Genes Within Uncultured Cyanobacterial Cells, C.J. Allender, G.R. Lecleir, J.M. Rinta-Kanto, R.L. Small, M.F. Satchwell, G.L. Boyer, Steven Wilhelm

Steven Wilhelm

While multiple phylogenetic markers have been used in the culture independent study of microcystin producing cyanobacteria, in only a few instances have multiple markers been studied within individual cells, and in all cases these studies have been conducted with cultured isolates. Here, we isolate and evaluate large DNA fragments (> 6 kb) encompassing two genes involved in microcystin biosynthesis (mcyA2 and mcyB1) and use them to identify the source of gene fragments found in water samples. Further investigation of these gene loci from individual cyanobacterial cells allowed for improved analysis of the genetic diversity within microcystin producers as …


Distribution Of Calcifying And Silicifying Phytoplankton In Relation To Environmental And Biogeochemical Parameters During The Late Stages Of The 2005 North East Atlantic Spring Bloom, K. Leblanc, C.E. Hare, Y. Feng, G.M. Berg, G.R. Ditullio, A. Neeley, I. Benner, C. Sprengel, A. Beck, S.A. Sanudo-Wilhemy, U. Passow, K. Klinck, J.M. Rowe, Steven Wilhelm, C.W. Brown, D.A. Hutchins Jan 2009

Distribution Of Calcifying And Silicifying Phytoplankton In Relation To Environmental And Biogeochemical Parameters During The Late Stages Of The 2005 North East Atlantic Spring Bloom, K. Leblanc, C.E. Hare, Y. Feng, G.M. Berg, G.R. Ditullio, A. Neeley, I. Benner, C. Sprengel, A. Beck, S.A. Sanudo-Wilhemy, U. Passow, K. Klinck, J.M. Rowe, Steven Wilhelm, C.W. Brown, D.A. Hutchins

Steven Wilhelm

The late stage of the North East Atlantic (NEA) spring bloom was investigated during June 2005 along a transect section from 45 to 66° N between 15 and 20° W in order to characterize the contribution of siliceous and calcareous phytoplankton groups and describe their distribution in relation to environmental factors. We measured several biogeochemical parameters such as nutrients, surface trace metals, algal pigments, biogenic silica (BSi), particulate inorganic carbon (PIC) or calcium carbonate, particulate organic carbon, nitrogen and phosphorus (POC, PON and POP, respectively), as well as transparent exopolymer particles (TEP). Results were compared with other studies undertaken in …


The Effects Of Increased Pco2 And Temperature On The North Atlantic Spring Bloom: I. The Phytoplankton Community And Biogeochemical Response, Y. Feng, C.E. Hare, K. Leblanc, J.M. Rose, Y Zhang, G.R. Ditullio, P. Lee, Steven Wilhelm, J.M. Rowe, J. Sun, N. Nemcek, C. Gueguen, U. Passow, I. Benner, C. Brown, D.A. Hutchins Jan 2009

The Effects Of Increased Pco2 And Temperature On The North Atlantic Spring Bloom: I. The Phytoplankton Community And Biogeochemical Response, Y. Feng, C.E. Hare, K. Leblanc, J.M. Rose, Y Zhang, G.R. Ditullio, P. Lee, Steven Wilhelm, J.M. Rowe, J. Sun, N. Nemcek, C. Gueguen, U. Passow, I. Benner, C. Brown, D.A. Hutchins

Steven Wilhelm

ABSTRACT: The North Atlantic spring bloom is one of the largest annual biological events in the ocean, and is characterized by dominance transitions from siliceous (diatoms) to calcareous (coccolithophores) algal groups. To study the effects of future global change on these phytoplankton and the biogeochemical cycles they mediate, a shipboard continuous culture experiment (Ecostat) was conducted in June 2005 during this transition period. Four treatments were examined: (1) 12°C and 390 ppm CO2 (ambient control), (2) 12°C and 690 ppm CO2 (high pCO2), (3) 16°C and 390 ppm CO2 (high temperature), and (4) 16°C and …


Effects Of Increased Pco2 And Temperature On The North Atlantic Spring Bloom: Iii. Dimethylsulfoniopropionate, P.A. Lee, J.R. Rudisill, A.R. Neeley, D.A. Hutchins, Y. Feng, C.E. Hare, K. Leblanc, J.M. Rose, Steven Wilhelm, J.M. Rowe, G.R. Ditullio Jan 2009

Effects Of Increased Pco2 And Temperature On The North Atlantic Spring Bloom: Iii. Dimethylsulfoniopropionate, P.A. Lee, J.R. Rudisill, A.R. Neeley, D.A. Hutchins, Y. Feng, C.E. Hare, K. Leblanc, J.M. Rose, Steven Wilhelm, J.M. Rowe, G.R. Ditullio

Steven Wilhelm

The CLAW hypothesis argues that a negative feedback mechanism involving phytoplankton-derived dimethylsulfoniopropionate (DMSP) could mitigate increasing sea surface temperatures that result from global warming. DMSP is converted to the climatically active dimethylsulfide (DMS), which is transferred to the atmosphere and photochemically oxidized to sulfate aerosols, leading to increases in planetary albedo and cooling of the Earth’s atmosphere. A shipboard incubation experiment was conducted to investigate the effects of increased temperature and pCO2 on the algal community structure of the North Atlantic spring bloom and their subsequent impact on particulate and dissolved DMSP concentrations (DMSPp and DMSPd). Under …


Role Of Chromodomain Helicase Dna-Binding Protein 2 In Dna Damage Response Signaling And Tumorigenesis., Thandi M. Onami, P. Nagarajan, S. Rajagopalan, S. Kania, R. Donnell, S. Venkatachalam Jan 2009

Role Of Chromodomain Helicase Dna-Binding Protein 2 In Dna Damage Response Signaling And Tumorigenesis., Thandi M. Onami, P. Nagarajan, S. Rajagopalan, S. Kania, R. Donnell, S. Venkatachalam

Thandi M. Onami

The chromodomain helicase DNA-binding proteins (CHDs) are known to affect transcription through their ability to remodel chromatin and modulate histone deacetylation. In an effort to understand the functional role of the CHD2 in mammals, we have generated a Chd2 mutant mouse model. Remarkably, the Chd2 protein appears to play a critical role in the development, hematopoiesis and tumor suppression. The Chd2 heterozygous mutant mice exhibit increased extramedullary hematopoiesis and susceptibility to lymphomas. At the cellular level, Chd2 mutants are defective in hematopoietic stem cell differentiation, accumulate higher levels of the chromatin-associated DNA damage response mediator, cH2AX, and exhibit an aberrant …


Cross-Talk In The Gut, Jennifer E. Dinalo, David A. Relman Jan 2009

Cross-Talk In The Gut, Jennifer E. Dinalo, David A. Relman

Jennifer E. Dinalo

Modulation of host signaling by the products of microbial activity in the gut may affect weight gain and fat formation.