415 research outputs found
Development of transgenic cucumber mosaic virus (CMV) resistant gerbera plants expressing CMV coat protein gene
121-130Gerbera (Gerbera jamesonii L.) has its immense importance to the floriculture industry worldwide. The gerbera flower
production has been hampered by various viruses, among them cucumber mosaic virus (CMV) has shown considerable
damage.As natural resistance to CMV is absent in gerbera, here, we have made an attempt to develop transgenic gerbera
plants expressing coat protein (CP) gene of CMV via Agrobacterium mediated transformation of base petiole explants for
genetic resistance to CMV infection. Among the 44 putative transgenic gerbera plant acclimatized, 39 were found positive
for integration of CP gene by polymerase chain reaction and southern hybridization assay using their specific primer and
probe respectively. Northern hybridization assay using CP gene specific probe confirmed the transcription of transgene in all
39 transgenic plants. These plants showed translation of CP during DAS-ELISA when tested with antiserum specific to CP
of CMV. These 39 plants when challenged by mechanical inoculations with CMV gerbera isolate showed virus resistance in
53% (21 out of 39) plants, virus tolerance (delayed mild symptom) in 33% (13/39) plants, while rest 12.8% (5/39) plants
showed severe disease symptoms. The CP mediated resistance of CMV in transgenic gerbera is being reported for the first
time from India
Dynamics of growth and weight transitions in a pediatric cohort from India
<p>Abstract</p> <p>Background</p> <p>There is paucity of information regarding time trends of weight status in children from rapidly developing economies like India. The aim of the study was to analyse the dynamics of growth and weight transitions in a cohort of school children from India.</p> <p>Methods</p> <p>A population of 25 228 children was selected using stratified random sampling method from schools in a contiguous area in Ernakulam District, Kerala, India. Weight and height were measured at two time points, one in 2003-04 and another in 2005-06. The paired data of 12 129 children aged 5-16 years were analysed for the study.</p> <p>Results</p> <p>The mean interval between the two surveys was 2.02 ± 0.32 years. The percentage of underweight, normal weight, overweight and obese children in the year 2003-04 were 38.4%, 56.6%, 3.7%, and 1.3% respectively. The corresponding figures in year 2005-06 were 29.9%, 63.6%, 4.8% and 1.7% respectively. Among the underweight children, 34.8% migrated to normal weight status and 0.1% migrated to overweight status. Conversion of underweight to normal weight predominated in urban area and girls. Among the normal weight children, 8.6% migrated to underweight, 4.1% migrated to overweight and 0.4% migrated to obesity. Conversion of normal weight to overweight status predominated in urban area, private schools and boys. Conversion of normal weight to underweight predominated in rural area, government schools and boys. Among the overweight children, 26.7% migrated to normal weight status, 16.4% became obese and 56.9% retained their overweight status. Of the obese children, 6.2% improved to normal weight status, 25.3% improved to overweight status and 68.5% remained as obese in 2005-06. There was significant difference in trends between socio demographic subgroups regarding conversion of underweight status to normal weight as well as normal weight status to overweight.</p> <p>Conclusion</p> <p>The study population is experiencing rapid growth and nutritional transitions characterised by a decline in the underweight population coupled with an escalation of the overweight population. The heterogeneous nature of this transition appears to be due to differences in socio demographic factors.</p
Imaging the equilibrium state and magnetization dynamics of partially built hard disk write heads
This is the final version of the article. Available from the American Institute of Physics via the DOI in this record.Four different designs of partially built hard disk write heads with a yoke comprising four repeats of NiFe (1nm)/CoFe (50nm) were studied by both x-ray photoemission electron microscopy (XPEEM) and time-resolved scanning Kerr microscopy (TRSKM). These techniques were used to investigate the static equilibrium domain configuration and the magnetodynamic response across the entire structure, respectively. Simulations and previous TRSKM studies have made proposals for the equilibrium domain configuration of similar structures, but no direct observation of the equilibrium state of the writers has yet been made. In this study, static XPEEM images of the equilibrium state of writer structures were acquired using x-ray magnetic circular dichroism as the contrast mechanism. These images suggest that the crystalline anisotropy dominates the equilibrium state domain configuration, but competition with shape anisotropy ultimately determines the stability of the equilibrium state. Dynamic TRSKM images were acquired from nominally identical devices. These images suggest that a longer confluence region may hinder flux conduction from the yoke into the pole tip: the shorter confluence region exhibits clear flux beaming along the symmetry axis, whereas the longer confluence region causes flux to conduct along one edge of the writer. The observed variations in dynamic response agree well with the differences in the equilibrium magnetization configuration visible in the XPEEM images, confirming that minor variations in the geometric design of the writer structure can have significant effects on the process of flux beaming.The authors gratefully acknowledge financial support from the Seagate Plan
A patient with glycogen storage disease type Ib presenting with acute myeloid leukemia (AML) bearing monosomy 7 and translocation t(3;8)(q26;q24) after 14 years of treatment with granulocyte colony-stimulating factor (G-CSF): A case report
<p>Abstract</p> <p>Introduction</p> <p>Glycogen storage disease type Ib is an autosomal recessive transmitted disorder of glycogen metabolism caused by mutations in the glucose-6-phosphate translocase gene on chromosome 11q23 and leads to disturbed glycogenolysis as well as gluconeogenesis. Besides hepatomegaly, growth retardation, hypoglycemia, hyperlactatemia, hyperuricemia and hyperlipidemia, patients suffer from neutropenia associated with functional defects predisposing for severe infections. In order to attenuate these complications, long-term treatment with granulocyte colony-stimulating factor is common but this is associated with an increased risk for acute myeloid leukemia or myelodysplastic syndromes in patients with inherited bone marrow failures such as severe congenital neutropenia. Onset of these myeloid malignancies is linked to cytogenetic aberrations involving chromosome 7. In addition, granulocyte colony-stimulating factor is known to stimulate proliferation of monosomy 7 cells <it>in vitro</it>. To our knowledge, we report for the first time a case report of a patient with glycogen storage disease type Ib, who developed acute myeloid leukemia with a classical monosomy 7 and acute myeloid leukemia-associated translocation t(3;8)(q26;q24) after 14 years of continuous treatment with granulocyte colony-stimulating factor.</p> <p>Case presentation</p> <p>A 28-year-old Turkish man with glycogen storage disease type Ib was admitted to our department because of dyspnea and increasing fatigue. He also presented with gum bleeding, bone pain in his legs, night sweats, recurrent episodes of fever with temperatures up to 39°C and hepatosplenomegaly.</p> <p>A blood count taken on the day of admission showed pancytopenia and a differential count displayed 30% blasts. A bone marrow biopsy was taken which showed a hypercellular marrow with dysplastic features of all three cell lines, while blast count was 20%. Classical cytogenetic analyses as well as fluorescence in situ hybridization showed a monosomy 7 with a translocation t(3;8)(q26;q24). Based on these findings, the diagnosis of acute myeloid leukemia was made.</p> <p>Conclusion</p> <p>Our observations suggest that bone marrow examinations including cytogenetic analysis should be carried out on a regular basis in patients with glycogen storage disease type Ib who are on long-term treatment with granulocyte colony-stimulating factor for severe neutropenia, since this treatment might also contribute to an increased risk for acute myeloid leukemia or myelodysplastic syndromes.</p
Effect of promoter architecture on the cell-to-cell variability in gene expression
According to recent experimental evidence, the architecture of a promoter,
defined as the number, strength and regulatory role of the operators that
control the promoter, plays a major role in determining the level of
cell-to-cell variability in gene expression. These quantitative experiments
call for a corresponding modeling effort that addresses the question of how
changes in promoter architecture affect noise in gene expression in a
systematic rather than case-by-case fashion. In this article, we make such a
systematic investigation, based on a simple microscopic model of gene
regulation that incorporates stochastic effects. In particular, we show how
operator strength and operator multiplicity affect this variability. We examine
different modes of transcription factor binding to complex promoters
(cooperative, independent, simultaneous) and how each of these affects the
level of variability in transcription product from cell-to-cell. We propose
that direct comparison between in vivo single-cell experiments and theoretical
predictions for the moments of the probability distribution of mRNA number per
cell can discriminate between different kinetic models of gene regulation.Comment: 35 pages, 6 figures, Submitte
A Genome-Wide Analysis of Promoter-Mediated Phenotypic Noise in Escherichia coli
Gene expression is subject to random perturbations that lead to fluctuations in the rate of protein production. As a consequence, for any given protein, genetically identical organisms living in a constant environment will contain different amounts of that particular protein, resulting in different phenotypes. This phenomenon is known as “phenotypic noise.” In bacterial systems, previous studies have shown that, for specific genes, both transcriptional and translational processes affect phenotypic noise. Here, we focus on how the promoter regions of genes affect noise and ask whether levels of promoter-mediated noise are correlated with genes' functional attributes, using data for over 60% of all promoters in Escherichia coli. We find that essential genes and genes with a high degree of evolutionary conservation have promoters that confer low levels of noise. We also find that the level of noise cannot be attributed to the evolutionary time that different genes have spent in the genome of E. coli. In contrast to previous results in eukaryotes, we find no association between promoter-mediated noise and gene expression plasticity. These results are consistent with the hypothesis that, in bacteria, natural selection can act to reduce gene expression noise and that some of this noise is controlled through the sequence of the promoter region alon
Genetic determinants of co-accessible chromatin regions in activated T cells across humans.
Over 90% of genetic variants associated with complex human traits map to non-coding regions, but little is understood about how they modulate gene regulation in health and disease. One possible mechanism is that genetic variants affect the activity of one or more cis-regulatory elements leading to gene expression variation in specific cell types. To identify such cases, we analyzed ATAC-seq and RNA-seq profiles from stimulated primary CD4+ T cells in up to 105 healthy donors. We found that regions of accessible chromatin (ATAC-peaks) are co-accessible at kilobase and megabase resolution, consistent with the three-dimensional chromatin organization measured by in situ Hi-C in T cells. Fifteen percent of genetic variants located within ATAC-peaks affected the accessibility of the corresponding peak (local-ATAC-QTLs). Local-ATAC-QTLs have the largest effects on co-accessible peaks, are associated with gene expression and are enriched for autoimmune disease variants. Our results provide insights into how natural genetic variants modulate cis-regulatory elements, in isolation or in concert, to influence gene expression
Bio-nanotechnology application in wastewater treatment
The nanoparticles have received high interest in the field of medicine and water purification, however, the nanomaterials produced by chemical and physical methods are considered hazardous, expensive, and leave behind harmful substances to the environment. This chapter aimed to focus on green-synthesized nanoparticles and their medical applications. Moreover, the chapter highlighted the applicability of the metallic nanoparticles (MNPs) in the inactivation of microbial cells due to their high surface and small particle size. Modifying nanomaterials produced by green-methods is safe, inexpensive, and easy. Therefore, the control and modification of nanoparticles and their properties were also discussed
Fracture properties of GGBFS-blended fly ash geopolymer concrete cured in ambient temperature
Fracture characteristics are important part of concrete design against brittle failure. Recently, fly ash geopolymer binder is gaining significant interest as a greener alternative to traditional ordinary Portland cement (OPC). Hence it is important to understand the failure behaviour of fly ash based geopolymers for safe design of structures built with such materials. This paper presents the fracture properties of ambient-cured geopolymer concrete (GPC). Notched beam specimens of GPC mixtures based mainly on fly ash and a small percentage of ground granulated blast furnace slag were subjected to three-point bending test to evaluate fracture behaviour. The effect of mixture proportions on the fracture properties were compared with control as well as OPC concrete. The results show that fracture properties are influenced by the mixture compositions. Presence of additional water affected fracture properties adversely. Fracture energy is generally governed by tensile strength which correlates with compressive strength. Critical stress intensity factor varies with the variation of flexural strength. Geopolymer concrete specimens showed similar load–deflection behaviour as OPC concrete specimens. The ambient cured GPC showed relatively more ductility than the previously reported heat cured GPC, which is comparable to the OPC specimens. Fly ash based GPC achieved relatively higher fracture energy and similar values of KIC as compared to those of OPC concrete of similar compressive strength. Thus, fly ash based GPC designed for curing in ambient condition can achieve fracture properties comparable to those of normal OPC concrete
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