Search results for "Actinomycete"

Heterotrophic microorganisms in deteriorated medieval wall paintings in southern Italian churches

2008

The Campania region in southern Italy is noted for its large number of churches that harbour invaluable frescoes, dated from the beginnings of the 4th up to the 13th century. The wall paintings represent an integral part of the monuments, and their deterioration constitutes a potentially significant loss for the world's cultural heritage. Heterotrophic microorganisms such as bacteria and mould can grow on the surface of paintings that contain a wide range of organic and inorganic constituents, and provide different ecological. niches that are exploited by a large variety of microbial. species. We isolated and identified the heterotrophic microorganisms found in the biodegraded medieval wall…

The Cell Cycle-Specific Growth-Inhibitory Factor Produced by Actinobacillus actinomycetemcomitans Is a Cytolethal Distending Toxin

1998

ABSTRACT Actinobacillus actinomycetemcomitans has been shown to produce a soluble cytotoxic factor(s) distinct from leukotoxin. We have identified in A. actinomycetemcomitans Y4 a cluster of genes encoding a cytolethal distending toxin (CDT). This new member of the CDT family is similar to the CDT produced by Haemophilus ducreyi . The CDT from A. actinomycetemcomitans was produced in Escherichia coli and was able to induce cell distension, growth arrest in G 2 /M phase, nucleus swelling, and chromatin fragmentation in HeLa cells. The three proteins, CDTA, -B and -C, encoded by the cdt locus were all required for toxin activity. Antiserum raised against recombinant CDTC completely inhibited …

Artificial Chromosomes to Explore and to Exploit Biosynthetic Capabilities of Actinomycetes

2012

Actinomycetes are an important source of biologically active compounds, like antibiotics, antitumor agents, and immunosuppressors. Genome sequencing is revealing that this class of microorganisms has larger genomes relative to other bacteria and uses a considerable fraction of its coding capacity (5–10%) for the production of mostly cryptic secondary metabolites. To access actinomycetes biosynthetic capabilities or to improve the pharmacokinetic properties and production yields of these chemically complex compounds, genetic manipulation of the producer strains can be performed. Heterologous expression in amenable hosts can be useful to exploit and to explore the genetic potential of actinom…

Dispersion from C

2019

Resonance assignment of intrinsically disordered proteins is remarkably challenging due to scant chemical shift dispersion arising from conformational heterogeneity. The challenge is even greater if repeating segments are present in the amino acid sequence. To forward unambiguous resonance assignment of intrinsically disordered proteins, we present iHACANCO, HACACON and (HACA)CONCAHA, three Hα-detected 4D experiments with Cα as an additional dimension. In addition, we present (HACA)CON(CA)NH and (HACA)N(CA)CONH, new 4D Hα-start, HN-detect experiments which have two NH dimensions to enhance peak dispersion in a sequential walk through C′, NH and HN, and provide more accurate NH/HN chemical s…

Microbiological assessment of the implant-abutment interface in different connections: cross-sectional study after 5 years of functional loading.

2014

Objective To evaluate the bacterial microflora present inside the implant connection and in the peri-implant sulcus fluid of healthy implants, and to analyze the relationships between these harboring sites for four different implant systems after at least 5 years of functional loading. Materials and methods A cross-sectional study was performed involving 40 patients treated with metal-ceramic cemented bridges supported by at least two healthy implants functionally loaded for 5 years. Four different implant-abutment connections were studied: external hexagon (control group), double internal hexagon (test group 1), internal hexagon with external collar (test group 2), and conical connection (…

Periodontal clinical and microbiological data in desquamative gingivitis patients.

2013

Objectives: A series of patients affected by desquamative gingivitis (DG) was investigated in order to evaluate relation patterns among clinical parameters relevant to plaque induced periodontitis, periodontal microbiological data and the presence of DG lesions. Patients and methods: Eight oral lichen planus (OLP) and four mucous membrane pemphigoid (MMP) patients were examined. Periodontal measurements (performed at six sites per tooth on all teeth) included probing depth (PD), gingival recession (REC), clinical attachment loss (CAL) and full mouth plaque (FMPS) and bleeding (FMBS) scores; the presence and the exact location (site by site) of DG lesions were carefully recorded. Sub-gingiva…

Analysis of the peri-implant microbiota in 90 dental implants and its relationship to crevicular fluid volume

2010

Objective: To evaluate the presence within the peri-implant sulcus of Tannerela forsythia (Tf), Porphyromonas gingivales (Pg), Treponema denticola (Td) and Aggregatibacter actinomycetemcomitans (Aa), and relate these bacteria to the peri-implant crevicular fluid volume (PICFV). Material and Method: A prospective and cross-sectional clinical case series study was made. For the measurement of crevicular fluid, use was made of the Periotron ® 8000 (Proflow Incorporated. New York, USA), measuring the volume in Periotron units (PU). For the detection of periodontopathogenic bacteria we used the IAI-PadoTest 4.5 (IAI Inc., IAI Institute, Zuchwil, Switzerland) - a system for the detection of Tf, P…

2021

Late embryogenesis abundant (LEA) proteins are important players in the management of responses to stressful conditions, such as drought, high salinity, and changes in temperature. Many LEA proteins do not have defined three-dimensional structures, so they are intrinsically disordered proteins (IDPs) and are often highly hydrophilic. Although LEA-like sequences have been identified in bacterial genomes, the functions of bacterial LEA proteins have been studied only recently. Sequence analysis of outer membrane interleukin receptor I (BilRI) from the oral pathogen Aggregatibacter actinomycetemcomitans indicated that it shared sequence similarity with group 3/3b/4 LEA proteins. Comprehensive …

Mutations in the rpoB and katG Genes Leading to Drug Resistance in Mycobacterium tuberculosis in Latvia

2002

ABSTRACT To characterize the genetic basis of drug resistance in Mycobacterium tuberculosis in Latvia, mutations involved in rifampin ( rpoB gene) and isoniazid ( katG gene) resistance in DNA from 19 drug-susceptible and 51 multidrug-resistant M. tuberculosis complex isolates were analyzed. The most frequent rpoB gene mutations found by the Line Probe assay were the S531L (14 of 34 isolates), D516V (7 of 34), H526D (4 of 34), and D516Y plus P535S (4 of 34) mutations. Direct sequencing of seven isolates with unclear results from Line Probe assay showed the presence of the L533P mutation and the Q510H plus H526Y (1 of 34) and D516V plus P535S (4 of 34) double mutations, neither of which has b…

Snapshot of Moving and Expanding Clones of Mycobacterium tuberculosis and Their Global Distribution Assessed by Spoligotyping in an International Stu…

2003

ABSTRACT The present update on the global distribution of Mycobacterium tuberculosis complex spoligotypes provides both the octal and binary descriptions of the spoligotypes for M. tuberculosis complex, including Mycobacterium bovis , from >90 countries (13,008 patterns grouped into 813 shared types containing 11,708 isolates and 1,300 orphan patterns). A number of potential indices were developed to summarize the information on the biogeographical specificity of a given shared type, as well as its geographical spreading (matching code and spreading index, respectively). To facilitate the analysis of hundreds of spoligotypes each made up of a binary succession of 43 bits of information, …