Removal of mismatched bases from synthetic genes by enzymatic mismatch cleavage

The success of long polynucleotide de novo synthesis is largely dependent on the quality and purity of the oligonucleotides used. Generally, the primary product of any synthesis reaction is directly cloned, and clones with correct products have to be identified. In this study, a novel strategy has been established for removing undesired sequence variants from primary gene synthesis products. Single base-pair mismatches, insertions and deletions were cleaved with specific endonucleases. Three different enzymes—T7 endonuclease I, T4 endonuclease VII and Escherichia coli endonuclease V—have been tested. As a model, a synthetic polynucleotide encoding the bacterial chloramphenicol-acetyltransferase (cat) was synthesized using different methods for one step polynucleotide synthesis based on ligation of oligonucleotides. The influence of enzymatic mismatch cleavage (EMC) as an error correction step on the frequency of correct products was analyzed by functional cloning of the synthetic cat and comparing the error rate with that of untreated products. Significant reduction of all mutation types was observed. Statistical analysis revealed that the T4 and E.coli endonucleases reduced the occurrence of mutations in cloned synthetic gene products. The EMC treatment was successful especially in the removal of deletions and insertions from the primary ligation products

К вопросу о дистанционном обучении в аэрокосмической отрасли

Данная статья содержит информацию о возможности применения дистанционного обучения в образовательном процессе для получения степени бакалавра или магистра, либо для получения сертификата о прохождении образовательного курса в области аэрокосмической инженерии. Также рассматриваются преимущества и недостатки электронного обучения в аэрокосмической сфере. Проводится сравнительный анализ различных программ дистанционного обучения в зарубежных странах по основным критериям: стоимость обучения, продолжительность и содержание курса, требования кстуденту и т.д. Кроме того, изучена распростран?нность онлайн обучения в аэрокосмической отрасли в России и выявлены возможные проблемы реализации дистанционного обучения в аэрокосмической инженерии.This article contains an information about the possibilities of applying distance learning in the educational process in order to earn bachelor's degree or master's degree, or to obtain a certificate of passing the educational course in the field of aerospace engineering. The advantages and disadvantages of e-learning in the aerospace field are also mentioned. Comparative analysis of various distance learning programs in foreign countries was made according to the main criteria: tuition fee, duration and course content, student requirements, etc. In addition, the prevalence of online learning in the aerospace industry in Russia and possible problems of implementation ofdistance learning in aerospace engineering are covered

The Numerical Simulation Application for Fire-Tube Boiler Heating Surface Safety Evaluation

The numerical simulation is applied for fire-tube boiler heating surface safety estimation. Thermal processes in an inflatable fire-tube furnace during its emergency operation were simulated using the finite volume method with Euler approximation and the implicit pressure based algorithm. Study results reproduce failures connected with increasing of impasse aerodynamic resistance. The method of these failures prediction is suggested. Simulation has shown that entering the amount of coolant into combustion volume results in burner fan incapability to overcome the impasse resistance of the furnace. The simulation results are visually confirmed during the inspection of emergency boilers

Fluorescence staining of live cyanobacterial cells suggest non-stringent chromosome segregation and absence of a connection between cytoplasmic and thylakoid membranes

<p>Abstract</p> <p>Background</p> <p>In spite of their abundance and importance, little is known about cyanobacterial cell biology and their cell cycle. During each cell cycle, chromosomes must be separated into future daughter cells, i.e. into both cell halves, which in many bacteria is achieved by an active machinery that operates during DNA replication. Many cyanobacteria contain multiple identical copies of the chromosome, but it is unknown how chromosomes are segregated into future daughter cells, and if an active or passive mechanism is operative. In addition to an outer and an inner cell membrane, cyanobacteria contain internal thylakoid membranes that carry the active photosynthetic machinery. It is unclear whether thylakoid membranes are invaginations of the inner cell membrane, or an independent membrane system.</p> <p>Results</p> <p>We have used different fluorescent dyes to study the organization of chromosomes and of cell and thylakoid membranes in live cyanobacterial cells. FM1-43 stained the outer and inner cytoplasmic membranes but did not enter the interior of the cell. In contrast, thylakoid membranes in unicellular <it>Synechocystis </it>cells became visible through a membrane-permeable stain only. Furthermore, continuous supply of the fluorescent dye FM1-43 resulted in the formation of one to four intracellular fluorescent structures in <it>Synechocystis </it>cells, within occurred within 30 to 60 minutes, and may represent membrane vesicles. Using fluorescent DNA stains, we found that <it>Synechocystis </it>genomic DNA is compacted in the cell centre that is devoid of thylakoid membranes. Nucleoids segregated very late in the cell cycle, just before complete closing of the division septum. In striking contrast to <it>Bacillus subtilis</it>, which possesses an active chromosome segregation machinery, fluorescence intensity of stained nucleoids differed considerably between the two <it>Synechocystis </it>daughter cells soon after cell division.</p> <p>Conclusion</p> <p>Our experiments strongly support the idea that the cytoplasmic and thylakoid membranes are not directly connected, but separate entities, in unicellular cyanobacteria. Our findings suggest that a transport system may exist between the cytoplasmic membrane and thylakoids, which could mediate the extension of thylakoid membranes and possibly also protein transport from the cytoplasmic membrane to thylakoid membranes. The cell cycle studies in <it>Synechocystis </it>sp. PCC 6803 show that the multiple chromosome copies per cell segregate very late in the cell cycle and in a much less stringent manner than in <it>B. subtilis </it>cells, indicating that chromosomes may become segregated randomly and in a passive fashion, possibly through constriction of the division septum.</p

EU-Osterweiterung und Outsourcing: Chance oder Gefahr?

Im Zuge der EU-Osterweiterung wird das Thema "Outsourcing" intensiv diskutiert. Für Prof. Dr. Wilfried Fuhrmann, Universität Potsdam, liegt "die Chance infolge der Osterweiterung mit dem regionalen Outsourcing ... im Druck auf Reduktion der Staatseingriffe". Stefanie Bechert und Gertraud Cellarius, Rationalisierungs- und Innovationszentrum der Deutschen Wirtschaft, Eschborn, gehen davon aus, dass "für die Mehrzahl der deutschen Unternehmen ... ein gezieltes Outsourcing ... in Frage (kommt)". Prof. Dr. Jürgen Weigand und Peter Kreutter, WHU Vallendar, sowie Dr. Steffen Kinkel, Fraunhofer Institut für Systemtechnik und Innovationsforschung, Karlsruhe, unterstreichen, dass die Beschäftigungseffekte für den inländischen Betrieb stark von der Strategie abhängen, die Unternehmen mit ihrer Auslandsproduktion verfolgen

EU-Osterweiterung und Outsourcing: Chance oder Gefahr?

Im Zuge der EU-Osterweiterung wird das Thema "Outsourcing" intensiv diskutiert. Für Prof. Dr. Wilfried Fuhrmann, Universität Potsdam, liegt "die Chance infolge der Osterweiterung mit dem regionalen Outsourcing ... im Druck auf Reduktion der Staatseingriffe". Stefanie Bechert und Gertraud Cellarius, Rationalisierungs- und Innovationszentrum der Deutschen Wirtschaft, Eschborn, gehen davon aus, dass "für die Mehrzahl der deutschen Unternehmen ... ein gezieltes Outsourcing ... in Frage (kommt)". Prof. Dr. Jürgen Weigand und Peter Kreutter, WHU Vallendar, sowie Dr. Steffen Kinkel, Fraunhofer Institut für Systemtechnik und Innovationsforschung, Karlsruhe, unterstreichen, dass die Beschäftigungseffekte für den inländischen Betrieb stark von der Strategie abhängen, die Unternehmen mit ihrer Auslandsproduktion verfolgen.EU-Erweiterung, Wettbewerb, Standort, Arbeitsplatz, Auslandsproduktion, Outsourcing, Abwanderung, Unternehmen, Industrie, Deutschland

Tailored Light Scattering through Hyperuniform Disorder in Self-Organized Arrays of High-Index Nanodisks

Arrays of nanoparticles exploited in light scattering applications commonly only feature either a periodic or a rather random arrangement of its constituents. For the periodic case, light scattering is mostly governed by the strong spatial correlations of the arrangement, expressed by the structure factor. For the random case, structural correlations cancel each other out and light scattering is mostly governed by the scattering properties of the individual scatterer, expressed by the form factor. In contrast to these extreme cases, it is shown here that hyperuniform disorder in self-organized large-area arrays of high refractive index nanodisks enables both structure and form factor to impact the resulting scattering pattern, offering novel means to tailor light scattering. The scattering response from the authors’ nearly hyperuniform interfaces can be exploited in a large variety of applications and constitutes a novel class of advanced optical materials

The N2K Consortium. II. A Transiting Hot Saturn Around HD 149026 With a Large Dense Core

Doppler measurements from Subaru and Keck have revealed radial velocity variations in the V=8.15, G0IV star HD 149026 consistent with a Saturn-Mass planet in a 2.8766 day orbit. Photometric observations at Fairborn Observatory have detected three complete transit events with depths of 0.003 mag at the predicted times of conjunction. HD 149026 is now the second brightest star with a transiting extrasolar planet. The mass of the star, based on interpolation of stellar evolutionary models, is 1.3 +/- 0.1 solar masses; together with the Doppler amplitude, K=43.3 m s^-1, we derive a planet mass Msin(i)=0.36 Mjup, and orbital radius of 0.042 AU. HD 149026 is chromospherically inactive and metal-rich with spectroscopically derived [Fe/H]=+0.36, Teff=6147 K, log g=4.26 and vsin(i)=6.0 km s^-1. Based on Teff and the stellar luminosity of 2.72 Lsun, we derive a stellar radius of 1.45 Rsun. Modeling of the three photometric transits provides an orbital inclination of 85.3 +/- 1.0 degrees and (including the uncertainty in the stellar radius) a planet radius of 0.725 +/- 0.05 Rjup. Models for this planet mass and radius suggest the presence of a ~67 Mearth core composed of elements heavier than hydrogen and helium. This substantial planet core would be difficult to construct by gravitational instability.Comment: 25 pages, 5 figures, accepted by the Astrophysical Journa

Intra-articular injections of high-molecular-weight hyaluronic acid have biphasic effects on joint inflammation and destruction in rat antigen-induced arthritis

To assess the potential use of hyaluronic acid (HA) as adjuvant therapy in rheumatoid arthritis, the anti-inflammatory and chondroprotective effects of HA were analysed in experimental rat antigen-induced arthritis (AIA). Lewis rats with AIA were subjected to short-term (days 1 and 8, n = 10) or long-term (days 1, 8, 15 and 22, n = 10) intra-articular treatment with microbially manufactured, high-molecular-weight HA (molecular weight, 1.7 × 10(6 )Da; 0.5 mg/dose). In both tests, 10 buffer-treated AIA rats served as arthritic controls and six healthy animals served as normal controls. Arthritis was monitored by weekly assessment of joint swelling and histological evaluation in the short-term test (day 8) and in the long-term test (day 29). Safranin O staining was employed to detect proteoglycan loss from the epiphyseal growth plate and the articular cartilage of the arthritic knee joint. Serum levels of IL-6, tumour necrosis factor alpha and glycosaminoglycans were measured by ELISA/kit systems (days 8 and 29). HA treatment did not significantly influence AIA in the short-term test (days 1 and 8) but did suppress early chronic AIA (day 15, P < 0.05); however, HA treatment tended to aggravate chronic AIA in the long-term test (day 29). HA completely prevented proteoglycan loss from the epiphyseal growth plate and articular cartilage on day 8, but induced proteoglycan loss from the epiphyseal growth plate on day 29. Similarly, HA inhibited the histological signs of acute inflammation and cartilage damage in the short-term test, but augmented acute and chronic inflammation as well as cartilage damage in the long-term test. Serum levels of IL-6, tumour necrosis factor alpha, and glycosaminoglycans were not influenced by HA. Local therapeutic effects of HA in AIA are clearly biphasic, with inhibition of inflammation and cartilage damage in the early chronic phase but with promotion of joint swelling, inflammation and cartilage damage in the late chronic phase