Measuring Energy Demands of Dynamic Remodeling Events During Embryogenesis in Live Drosophila Embryos

Embryonic development is a complex process requiring dynamic cell movements to create complex tissue structures. We assume that these embryonic dynamic remodeling events are highly energy intensive and that this energy expenditure is mediated by mitochondria. However, this has been difficult to demonstrate in live embryos. Convergent extension of the Drosophila neuroectoderm is a promising system to study the bioenergetics of tissue remodeling because it changes from a static to a dynamically remodeling tissue with temporal precision. We hypothesize that the switch from static to dynamic development at the onset of convergent extension will be accompanied by an increase in metabolic energy production. Our method of measuring metabolic production is through the use of the Seahorse XF HS Mini Analyzer, which is capable of measuring bioenergetic processes in small numbers of cells. Notably, the Seahorse Analyzer measures Oxygen Consumption Rate (OCR) and Extracellular Acidification Rate (ECAR), which are indicators of energy production. I expect that an increase in metabolic production will be indicated by an increase in OCR and a drop in ECAR. By measuring these bioenergetic markers before and during convergent extension, the effects of dynamic tissue development on metabolism can be uncovered. All empty control wells resulted in OCR and ECAR readings near zero, and all wells with embryos measured between 100-300 pmol/min OCR. The Seahorse Analyzer could detect the presence of live embryos but was unable to detect consistent differences between one and multiple embryos in a well. These results were incapable of demonstrating whether metabolism increases or remains constant, as we did see an effect, but the data lacked consistency and the effect did not scale with the number of embryos

Measuring Energy Demands of Dynamic Remodeling Events During Embryogenesis in Live Drosophila Embryos

Embryonic development is a complex process requiring dynamic cell movements to create complex tissue structures. We assume that these embryonic dynamic remodeling events are highly energy intensive and that this energy expenditure is mediated by mitochondria. However, this has been difficult to demonstrate in live embryos. Convergent extension of the Drosophila neuroectoderm is a promising system to study the bioenergetics of tissue remodeling because it changes from a static to a dynamically remodeling tissue with temporal precision. We hypothesize that the switch from static to dynamic development at the onset of convergent extension will be accompanied by an increase in metabolic energy production. Our method of measuring metabolic production is through the use of the Seahorse XF HS Mini Analyzer, which is capable of measuring bioenergetic processes in small numbers of cells. Notably, the Seahorse Analyzer measures Oxygen Consumption Rate (OCR) and Extracellular Acidification Rate (ECAR), which are indicators of energy production. I expect that an increase in metabolic production will be indicated by an increase in OCR and a drop in ECAR. By measuring these bioenergetic markers before and during convergent extension, the effects of dynamic tissue development on metabolism can be uncovered. All empty control wells resulted in OCR and ECAR readings near zero, and all wells with embryos measured between 100-300 pmol/min OCR. The Seahorse Analyzer could detect the presence of live embryos but was unable to detect consistent differences between one and multiple embryos in a well. These results were incapable of demonstrating whether metabolism increases or remains constant, as we did see an effect, but the data lacked consistency and the effect did not scale with the number of embryos

Intensified array camera imaging of solid surface combustion aboard the NASA Learjet

An intensified array camera was used to image weakly luminous flames spreading over thermally thin paper samples in a low gravity environment aboard the NASA-Lewis Learjet. The aircraft offers 10 to 20 sec of reduced gravity during execution of a Keplerian trajectory and allows the use of instrumentation that is delicate or requires higher electrical power than is available in drop towers. The intensified array camera is a charge intensified device type that responds to light between 400 and 900 nm and has a minimum sensitivity of 10(exp 6) footcandles. The paper sample, either ashless filter paper or a lab wiper, burns inside a sealed chamber which is filled with 21, 18, or 15 pct. oxygen in nitrogen at one atmosphere. The camera views the edge of the paper and its output is recorded on videotape. Flame positions are measured every 0.1 sec to calculate flame spread rates. Comparisons with drop tower data indicate that the flame shapes and spread rates are affected by the residual g level in the aircraft

Pure Basaloid Squamous Cell Carcinoma of the Uterine Cervix: A Case Report

Basaloid squamous cell carcinoma of the uterine cervix is an extremely rare malignancy of the female genital tract with a poorer clinical outcome than squamous cell carcinoma of the uterine cervix. We report a case of pure basaloid squamous cell carcinoma of the uterine cervix. A 70-yr-old woman with vaginal bleeding was referred to our institute. A basaloid squamous cell carcinoma of the uterine cervix, of International Federation of Gynecology and Obstetrics (FIGO) stage Ib1, was diagnosed by a loop electrosurgical excision procedure cone biopsy. A radical hysterectomy was performed, along with bilateral salpingo-oophorectomy, pelvic lymph node dissection, and para-aortic lymph node sampling. Pathologic findings were consistent with a basaloid squamous cell carcinoma confined to the cervix without an extracervical tumor. No further treatment was administered and there was no clinical evidence of recurrence during the 12 months of follow-up. Follow-up for the patient is ongoing. Although basaloid squamous cell carcinoma of the uterine cervix is thought to behave aggressively, accumulation of data on these rare tumors is necessary to determine whether their behavior differs significantly from that of conventional cervical squamous cell carcinoma of similar clinical stage. These data would be useful for defining the best diagnosis and treatment for these rare tumors

Genome Diversity of Epstein-Barr Virus from Multiple Tumor Types and Normal Infection

Epstein-Barr virus (EBV) infects most of the world’s population and is causally associated with several human cancers, but little is known about how EBV genetic variation might influence infection or EBV-associated disease. There are currently no published wild-type EBV genome sequences from a healthy individual and very few genomes from EBV-associated diseases. We have sequenced 71 geographically distinct EBV strains from cell lines, multiple types of primary tumor, and blood samples and the first EBV genome from the saliva of a healthy carrier. We show that the established genome map of EBV accurately represents all strains sequenced, but novel deletions are present in a few isolates. We have increased the number of type 2 EBV genomes sequenced from one to 12 and establish that the type 1/type 2 classification is a major feature of EBV genome variation, defined almost exclusively by variation of EBNA2 and EBNA3 genes, but geographic variation is also present. Single nucleotide polymorphism (SNP) density varies substantially across all known open reading frames and is highest in latency-associated genes. Some T-cell epitope sequences in EBNA3 genes show extensive variation across strains, and we identify codons under positive selection, both important considerations for the development of vaccines and T-cell therapy. We also provide new evidence for recombination between strains, which provides a further mechanism for the generation of diversity. Our results provide the first global view of EBV sequence variation and demonstrate an effective method for sequencing large numbers of genomes to further understand the genetics of EBV infection

Forces During Bacteriophage DNA Packaging and Ejection

The conjunction of insights from structural biology, solution biochemistry, genetics and single molecule biophysics has provided a renewed impetus for the construction of quantitative models of biological processes. One area that has been a beneficiary of these experimental techniques is the study of viruses. In this paper we describe how the insights obtained from such experiments can be utilized to construct physical models of processes in the viral life cycle. We focus on dsDNA bacteriophages and show that the bending elasticity of DNA and its electrostatics in solution can be combined to determine the forces experienced during packaging and ejection of the viral genome. Furthermore, we quantitatively analyze the effect of fluid viscosity and capsid expansion on the forces experienced during packaging. Finally, we present a model for DNA ejection from bacteriophages based on the hypothesis that the energy stored in the tightly packed genome within the capsid leads to its forceful ejection. The predictions of our model can be tested through experiments in vitro where DNA ejection is inhibited by the application of external osmotic pressure

Asymmetric Organocatalytic C-C Bond Forming Reactions with Organoboron Compounds: A Mechanistic Survey

The recent development of asymmetric organocatalytic C-C bond forming reactions involving organoboranes has attracted big interest in the synthetic community. Asymmetric organocatalytic additions to enones, aldehydes, ketones, imines, dienes, and related systems can be carried out with different organoboron compounds (boronic acids and esters and trifluoroborate salts) to give products with very good yields and enantiomeric ratios. In particular, many BINOL and α-hydroxyacid derivatives have been used as chiral organocatalysts. In this review, we describe the mechanisms that have been proposed based on theoretical and experimental studies for asymmetric organocatalytic C-C bond forming reactions with organoboron compounds. The mechanistic understanding that has been gained should contribute to the progress of this promising area of organic chemistry.Fil: Simonetti, Sebastián Osvaldo. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Rosario. Instituto de Química Rosario. Universidad Nacional de Rosario. Facultad de Ciencias Bioquímicas y Farmacéuticas. Instituto de Química Rosario; ArgentinaFil: Pellegrinet, Silvina Carla. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Rosario. Instituto de Química Rosario. Universidad Nacional de Rosario. Facultad de Ciencias Bioquímicas y Farmacéuticas. Instituto de Química Rosario; Argentin

Genome diversity of Epstein-Barr virus from multiple tumor types and normal infection

pstein-Barr virus (EBV) infects most of the world's population and is causally associated with several human cancers, but little is known about how EBV genetic variation might influence infection or EBV-associated disease. There are currently no published wild-type EBV genome sequences from a healthy individual and very few genomes from EBV-associated diseases. We have sequenced 71 geographically distinct EBV strains from cell lines, multiple types of primary tumor, and blood samples and the first EBV genome from the saliva of a healthy carrier. We show that the established genome map of EBV accurately represents all strains sequenced, but novel deletions are present in a few isolates. We have increased the number of type 2 EBV genomes sequenced from one to 12 and establish that the type 1/type 2 classification is a major feature of EBV genome variation, defined almost exclusively by variation of EBNA2 and EBNA3 genes, but geographic variation is also present. Single nucleotide polymorphism (SNP) density varies substantially across all known open reading frames and is highest in latency-associated genes. Some T-cell epitope sequences in EBNA3 genes show extensive variation across strains, and we identify codons under positive selection, both important considerations for the development of vaccines and T-cell therapy. We also provide new evidence for recombination between strains, which provides a further mechanism for the generation of diversity. Our results provide the first global view of EBV sequence variation and demonstrate an effective method for sequencing large numbers of genomes to further understand the genetics of EBV infection. IMPORTANCE: Most people in the world are infected by Epstein-Barr virus (EBV), and it causes several human diseases, which occur at very different rates in different parts of the world and are linked to host immune system variation. Natural variation in EBV DNA sequence may be important for normal infection and for causing disease. Here we used rapid, cost-effective sequencing to determine 71 new EBV sequences from different sample types and locations worldwide. We showed geographic variation in EBV genomes and identified the most variable parts of the genome. We identified protein sequences that seem to have been selected by the host immune system and detected variability in known immune epitopes. This gives the first overview of EBV genome variation, important for designing vaccines and immune therapy for EBV, and provides techniques to investigate relationships between viral sequence variation and EBV-associated diseases

The effects of sample position and gas flow pattern on the sintering of a 7xxx aluminum alloy

The effects of sample position and gas flow pattern on the sintering of a 7xxx aluminum alloy Al-7Zn-2.5Mg-1Cu in flowing nitrogen have been investigated both experimentally and numerically. The near-surface pore distribution and sintered density of the samples show a strong dependency on the sample separation distance over the range from 2 mm to 40 mm. The open porosity in each sample increases with increasing separation distance while the closed porosity remains essentially unchanged. A two-dimensional computational fluid dynamics (CFD) model has been developed to analyze the gas flow behavior near the sample surfaces during isothermal sintering. The streamlines, velocity profile, and volume flow rate in the cavity between each two samples are presented as a function of the sample separation distance at a fixed nitrogen flow rate of 6 L/min. The CFD modeling results provide essential details for understanding the near-surface pore distribution and density of the sintered samples. It is proposed that the different gas flow patterns near the sample surfaces result in variations of the oxygen content from the incoming nitrogen flow in the local sintering atmosphere, which affects the self-gettering process of the aluminum compacts during sintering. This leads to the development of different near-surface pore distributions and sintered densities

Singular Fermi Liquids

An introductory survey of the theoretical ideas and calculations and the experimental results which depart from Landau Fermi-liquids is presented. Common themes and possible routes to the singularities leading to the breakdown of Landau Fermi liquids are categorized following an elementary discussion of the theory. Soluble examples of Singular Fermi liquids (often called Non-Fermi liquids) include models of impurities in metals with special symmetries and one-dimensional interacting fermions. A review of these is followed by a discussion of Singular Fermi liquids in a wide variety of experimental situations and theoretical models. These include the effects of low-energy collective fluctuations, gauge fields due either to symmetries in the hamiltonian or possible dynamically generated symmetries, fluctuations around quantum critical points, the normal state of high temperature superconductors and the two-dimensional metallic state. For the last three systems, the principal experimental results are summarized and the outstanding theoretical issues highlighted.Comment: 170 pages; submitted to Physics Reports; a single pdf file with high quality figures is available from http://www.lorentz.leidenuniv.nl/~saarloo