scholarly journals Characterization of a microcystin and detection of microcystin synthetase genes from a Brazilian isolate of Nostoc

Toxicon ◽  
2010 ◽  
Vol 55 (4) ◽  
pp. 846-854 ◽  
Author(s):  
Diego Bonaldo Genuário ◽  
Maria Estela Silva-Stenico ◽  
Martin Welker ◽  
Luiz Alberto Beraldo Moraes ◽  
Marli Fátima Fiore
Keyword(s):  
Brazilian Isolate ◽  
Microcystin Synthetase

scholarly journals Isolation and antigenic characterization of human immunodeficiency virus (HIV) in Brazil

1987 ◽  
Vol 82 (4) ◽  
pp. 453-456 ◽  
Author(s):  
B. Galvão-Castro ◽  
J. Ivo-dos-Santos ◽  
J. C. Couto-Fernandez ◽  
V. Bongertz ◽  
Dumith Chequer-Bou-Habib ◽  
...  
Keyword(s):  
Human Immunodeficiency Virus ◽  
Western Blot ◽  
Blot Analysis ◽  
Envelope Glycoprotein ◽  
Brazilian Isolate ◽  
Antigenic Characterization ◽  
Immunodeficiency Virus ◽  
Human Immunodeficiency Viruses ◽  
Hiv 1

A retrovirus infecting a Brazilian AIDS patient was isolated and characterized in terms of its reactivity with sera from individuals infected with human immunodeficiency viruses 1 and 2 (HIV-1 and HIV-2). The Western blot analysis revealed that the Brazilian isolate is very similar to the well characterized HIV-1 strain. The serum of the patient from whom the virus was isolated did not react with the 140 kDa envelope glycoprotein specific for HIV-2.

scholarly journals Natural Variation in the Microcystin Synthetase Operon mcyABC and Impact on Microcystin Production in Microcystis Strains

2003 ◽  
Vol 185 (9) ◽  
pp. 2774-2785 ◽  
Author(s):  
Bjørg Mikalsen ◽  
Gudrun Boison ◽  
Olav M. Skulberg ◽  
Jutta Fastner ◽  
William Davies ◽  
...  
Keyword(s):  
Genetic Variation ◽  
Natural Variation ◽  
Gene Loss ◽  
Genetic Characterization ◽  
Adenylation Domain ◽  
Ionization Time ◽  
Microcystin Synthetase ◽  
Flight Mass Spectrometry ◽  
Microcystin Production

ABSTRACT Toxic Microcystis strains often produce several isoforms of the cyclic hepatotoxin microcystin, and more than 65 isoforms are known. This has been attributed to relaxed substrate specificity of the adenylation domain. Our results show that in addition to this, variability is also caused by genetic variation in the microcystin synthetase genes. Genetic characterization of a region of the adenylation domain in module mcyB1 resulted in identification of two groups of genetic variants in closely related Microcystis strains. Sequence analyses suggested that the genetic variation is due to recombination events between mcyB1 and the corresponding domains in mcyC. Each variant could be correlated to a particular microcystin isoform profile, as identified by matrix-assisted laser desorption ionization-time of flight mass spectrometry. Among the Microcystis species studied, we found 11 strains containing different variants of the mcyABC gene cluster and 7 strains lacking the genes. Furthermore, there is no concordance between the phylogenies generated with mcyB1, 16S ribosomal DNA, and DNA fingerprinting. Collectively, these results suggest that recombination between imperfect repeats, gene loss, and horizontal gene transfer can explain the distribution and variation within the mcyABC operon.

Structural Characterization of in Vitro and in Vivo Intermediates on the Loading Module of Microcystin Synthetase

2006 ◽  
Vol 1 (2) ◽  
pp. 93-102 ◽  
Author(s):  
Leslie M. Hicks ◽  
Michelle C. Moffitt ◽  
Laura L. Beer ◽  
Bradley S. Moore ◽  
Neil L. Kelleher
Keyword(s):  
Structural Characterization ◽  
Microcystin Synthetase

scholarly journals Characterization of a Peruvian isolate of Metarhizium anisopliae var. acridum, a pathogen of grasshoppers

2003 ◽  
Vol 38 (12) ◽  
pp. 1469-1475 ◽  
Author(s):  
Bonifácio Peixoto Magalhães ◽  
Myrian Silvana Tigano ◽  
Irene Martins ◽  
Heloisa Frazão ◽  
Hilda Gómez Ramirez
Keyword(s):  
Metarhizium Anisopliae ◽  
Brazilian Isolate ◽  
Crop Pest ◽  
Growth Profiles ◽  
Similar Growth ◽  
Metarhizium Anisopliae Var Acridum

The objective of this study was to characterize the Peruvian isolate of Metarhizium anisopliae var. acridum, CG 863, obtained from the grasshopper Schistocerca interrita, a crop pest in Peru. The characterization was done by comparing this isolate with two other ones of M. anisopliae var. acridum, from Brazil and Australia, and with an isolate of M. anisopliae var. anisopliae. The three M. anisopliae var. acridum isolates had similar growth profiles in agar plates at 25°C and 37°C, and similar RAPD patterns according to the analysis of three primers. However, regarding these parameters and conidial size, these isolates were very distinct when compared to M. anisopliae var. anisopliae isolate. Bioassays indicated that the Peruvian isolate is as pathogenic as the Brazilian isolate against nymphs of Rhammatocerus schistocercoides.

Morphological Characterization of Mycobacteriophage R1

1974 ◽  
Vol 32 ◽  
pp. 254-255
Author(s):  
B. L. Soloff ◽  
T. A. Rado
Keyword(s):  
Carbon Source ◽  
Stationary Phase ◽  
Growth Phase ◽  
Minimal Medium ◽  
Morphological Characterization ◽  
Logarithmic Growth Phase ◽  
Complete Lysis ◽  
Lysogenic Culture ◽  
Logarithmic Growth

Mycobacteriophage R1 was originally isolated from a lysogenic culture of M. butyricum. The virus was propagated on a leucine-requiring derivative of M. smegmatis, 607 leu−, isolated by nitrosoguanidine mutagenesis of typestrain ATCC 607. Growth was accomplished in a minimal medium containing glycerol and glucose as carbon source and enriched by the addition of 80 μg/ ml L-leucine. Bacteria in early logarithmic growth phase were infected with virus at a multiplicity of 5, and incubated with aeration for 8 hours. The partially lysed suspension was diluted 1:10 in growth medium and incubated for a further 8 hours. This permitted stationary phase cells to re-enter logarithmic growth and resulted in complete lysis of the culture.

AEM analysis of crystallization in Ti-based amorphous alloys

1983 ◽  
Vol 41 ◽  
pp. 270-271
Author(s):  
A.R. Pelton ◽  
A.F. Marshall ◽  
Y.S. Lee
Keyword(s):  
Magnetic Properties ◽  
Amorphous Alloys ◽  
Amorphous Materials ◽  
Isothermal Annealing ◽  
Amorphous Matrix ◽  
Nucleation And Growth ◽  
Current Interest ◽  
Amorphous Films ◽  
Electrical And Magnetic Properties

Amorphous materials are of current interest due to their desirable mechanical, electrical and magnetic properties. Furthermore, crystallizing amorphous alloys provides an avenue for discerning sequential and competitive phases thus allowing access to otherwise inaccessible crystalline structures. Previous studies have shown the benefits of using AEM to determine crystal structures and compositions of partially crystallized alloys. The present paper will discuss the AEM characterization of crystallized Cu-Ti and Ni-Ti amorphous films.Cu60Ti40: The amorphous alloy Cu60Ti40, when continuously heated, forms a simple intermediate, macrocrystalline phase which then transforms to the ordered, equilibrium Cu3Ti2 phase. However, contrary to what one would expect from kinetic considerations, isothermal annealing below the isochronal crystallization temperature results in direct nucleation and growth of Cu3Ti2 from the amorphous matrix.

Characterization of Coherent, Ordered Precipitates in Nickel-Base Alloys

1973 ◽  
Vol 31 ◽  
pp. 144-145
Author(s):  
B. H. Kear ◽  
J. M. Oblak
Keyword(s):  
Stable Phase ◽  
Nickel Base Superalloy ◽  
Alloy 718 ◽  
Commercial Alloy ◽  
Precipitate Morphology ◽  
Continuous Precipitation ◽  
Nickel Base ◽  
Base Superalloy ◽  
Strengthening Precipitate

A nickel-base superalloy is essentially a Ni/Cr solid solution hardened by additions of Al (Ti, Nb, etc.) to precipitate a coherent, ordered phase. In most commercial alloy systems, e.g. B-1900, IN-100 and Mar-M200, the stable precipitate is Ni3 (Al,Ti) γ′, with an LI2structure. In A lloy 901 the normal precipitate is metastable Nis Ti3 γ′ ; the stable phase is a hexagonal Do2 4 structure. In Alloy 718 the strengthening precipitate is metastable γ″, which has a body-centered tetragonal D022 structure.Precipitate MorphologyIn most systems the ordered γ′ phase forms by a continuous precipitation re-action, which gives rise to a uniform intragranular dispersion of precipitate particles. For zero γ/γ′ misfit, the γ′ precipitates assume a spheroidal.

The Use of Advanced Analytical Techniques for Characterization of the Chemical, Physical, and Crystallographic Nature of a Surface

1973 ◽  
Vol 31 ◽  
pp. 132-133 ◽  
Author(s):  
R. E. Herfert
Keyword(s):  
Surface Characterization ◽  
Analytical Techniques ◽  
X Ray Diffraction ◽  
Depth Of Penetration ◽  
X Ray ◽  
The Past ◽  
Transmission Electron ◽  
Scanning Electron

Studies of the nature of a surface, either metallic or nonmetallic, in the past, have been limited to the instrumentation available for these measurements. In the past, optical microscopy, replica transmission electron microscopy, electron or X-ray diffraction and optical or X-ray spectroscopy have provided the means of surface characterization. Actually, some of these techniques are not purely surface; the depth of penetration may be a few thousands of an inch. Within the last five years, instrumentation has been made available which now makes it practical for use to study the outer few 100A of layers and characterize it completely from a chemical, physical, and crystallographic standpoint. The scanning electron microscope (SEM) provides a means of viewing the surface of a material in situ to magnifications as high as 250,000X.

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