1,720,991 research outputs found
Chromosome polymorphism among strains of Hansenula polymorpha (syn. Pichia angusta)
No full textContour-clamped homogeneous electrophoresis and an embedded-agarose method of sample preparation were combined to carry out an analysis of the chromosome sets of nine strains of Hansenula polymorpha (syn. Pichia angusta). Chromosomal DNA molecules could be separated into a series of bands ranging, approximately, from 650 up to 2,200 kb in size. Polymorphism of the electrophoretic pattern was demonstrated among the strains investigated in this study. Cross-hybridization between H. polymorpha and Saccharomyces cerevisiae ribosomal DNA was also observed
Prevalence, species differentiation and toxigenicity of Aeromonas strains in childhood gastroenteritis cases and in controls
No full textIn a 1-year period (January to December 1984), Aeromonas strains were isolated from feces of 21 of 561 (3.7%) children with gastroenteritis and from 12 of 576 (2.1%) children without intestinal disturbances (controls). The difference between the two isolation rates was not significant (X2 = 2.2; P > 0.05). In five cases of illness other intestinal pathogens were isolated together with Aeromonas in the same stool sample. A total of 39 Aeromonas strains were detected since in some cases aeromonads with different biochemical characteristics were obtained from the same stool sample. Of the 39 Aeromonas isolates, 6 strains (5 from patients) were Aeromonas hydrophila, 5 strains (3 from patients) were Aeromonas sobria, and 26 strains (18 from patients) were Aeromonas caviae; 2 strains isolated from controls did not ferment sucrose and were considered a distinct group of Aeromonas. We found no significant difference between the prevalence of each of these species from patients and the prevalence from controls. We found no significant difference in the prevalence of enterotoxinproducing strains (suckling mouse model), cytotoxin-producing strains (HEp-2 cell model), or hemolysinproducing strains (rabbit erythrocyte model) between patients and controls. In our geographical region there is no evidence that Aeromonas species are primary intestinal pathogens in children
Size of the Streptococcus Mutans GS-5 chromosome as determined by pulsed field gel electrophoresis
No full textRare cutting restriction endonucleases were used to cut the Streptococcus mutans chromosome into large fragments. Restriction enzymes utilizing recognition sites containing 6-, 7-, or 8-base-pair sequences with only G and C nucleotides produced few fragments, most of which were >100 kilobase pairs in size. Addition of the fragments from digests of SmaI, NotI, ApaI, RsrII, and EagI yielded a molecular size for the S. mutans GS-5 genome of 2,819 ± 60 kilobase pairs
Presence of antibacterial peptides on the laid egg chorion of the medfly Ceratitis capitata
No full textFemale reproductive accessory glands of the medfly Ceratitis capitata produce a secretion with antibacterial activity mainly ascribed to ceratotoxin peptides. To study whether the secretion from the accessory glands of the female protects the eggs and early larva from microbes, we examined whether ceratotoxins and other accessory gland components could be found on the egg surface. This was found to be the case; a water-soluble material with the same protein and antibacterial pattern as that of the accessory gland secretion was recovered from the laid egg surface and was observed as electrondense, clustered droplets over the outer exochorion. Such material showed the same electrophoretic pattern in both mated and virgin females. These findings indicate that the accessory gland secretion is spread, at oviposition, onto the eggs producing an antibacterial coating, irrespective of fertilization. This is the first report of antimicrobial components recovered from a material layered on insect laid eggs
A putative sigma factor from Streptomyces sp. strain A21 can activate the expression of the cryptic operon bgl in Escherichia coli K-12
No full textStreptomyces sp A21 is a cellulolytic strain isolated from soil which was assigned to the genus Streptomyces on the basis of distinctive morphological features. A genomic library of A21 DNA has been constructed and transformed into Escherichia coli K-12 using a high-copy-number vector. One of the recombinant plasmids activates the cryptic bgl operon when inserted into appropriate strains. The complete sequence of the 1629-bp A21 DNA fragment has been determined. The analysis revealed the presence of an ORF whose putative product shows a high degree of similarity to RNA polymerase sigma factors; we therefore designated the gene psfS ((P) under bar utative (s) under bar igma (f) under bar actor, (S) under bar treptomyces). Mapping of the 5' terminus of transcript by primer extension indicated that PsfS induces transcription initiation within the bgl promoter-silencer region
Restriction enzyme and DNA hybridization analysis of cellulolytic Streptomyces isolates of different origin
No full textStreptomyces rochei A2 endoglucanase (eglS) and β-glucosidase (bgs1) genes were used as probes to survey their distribution among 16 Streptomyces strains isolated from different sources and characterized for their cellulolytic activities. The eglS probe hybridized to the genomic DNA of 12 strains with a restriction pattern different from that of S. rochei A2. The DNA from all strains, except one, hybridized with the bgs1 probe and one strain showed the same restriction pattern as seen in S. rochei A2. The sequence localized by the eglS probe in S. thermoviolaceus and the one localized by the bgs1 probe in strain EC1 were cloned and expressed in E. coli in plasmids pTAE and pCSF203, respectively. The restriction maps showed that the cloned genes were identical to eglS and bgs1. The restriction enzyme analysis of genomic DNA from all the strains identified nine different groups, each characterized by a distinctive pattern and in agreement with the results of the hybridization experiments
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Arterial thrombosis triggered by methotrexate-induced hyperhomocysteinemia in a systemic lupus erythematosus patient with antiphospholipid antibodies
No full textAbstract Systemic lupus erythematosus (SLE) patients have an increased risk of cardiovascular disease and thrombotic events, and the presence of antiphospholipid antibodies further raises the risk of these complications. Here we report a case of a patient with SLE and triple positivity for antiphospholipid antibodies who developed a popliteal artery thrombosis in the context of a severe hyperhomocysteinemia after the introduction of methotrexate (MTX) treatment. MTX is one of the most prescribed medications for a wide spectrum of autoimmune diseases, including SLE. On the other hand, by interfering with folate metabolism, it may induce hyperhomocysteinemia, which, in turn, may increase the risk of vascular complications. Current recommendations suggest screening and, when possible, treating classical and disease-related cardiovascular risk factors in all lupus patients. Based on what observed in our case, we suggest a follow-up of homocysteine levels after the introduction of drugs capable of inducing hyperhomocysteinemia, such as MTX, in SLE patients at high cardiovascular risk
Variations on the Author
Full text link“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
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