Search results for "bacteri"
showing 10 items of 5466 documents
New alkaloid antibiotics that target the DNA topoisomerase I of Streptococcus pneumoniae
2011
16 pags, 3 figs, 3 tabs
8-N(3)-3'-biotinyl-ATP, a novel monofunctional reagent: differences in the F(1)- and V(1)-ATPases by means of the ATP analogue.
2001
A novel photoaffinity label, 8-N(3)-3'-biotinyl-ATP, has been synthesized. The introduction of an additional biotin residue is advantageous for easy detection of labeled proteins. This could be first tested by reaction with the F(1)-ATPase from the thermophilic bacterium PS3 (TF(1)). UV irradiation of TF(1) in the presence of 8-N(3)-3'-biotinyl-ATP results in a nucleotide-dependent binding of the analogue in the noncatalytic alpha and the catalytic beta subunits of TF(1), demonstrating the suitability of this analogue as a potential photoaffinity label. Reaction with the V(1)-ATPase, however, led to labeling of subunit E, which has been suggested as a structural and functional homologue of …
Structural mechanism of signal transduction in a phytochrome histidine kinase
2022
AbstractPhytochrome proteins detect red/far-red light to guide the growth, motion, development and reproduction in plants, fungi, and bacteria. Bacterial phytochromes commonly function as an entrance signal in two-component sensory systems. Despite the availability of three-dimensional structures of phytochromes and other two-component proteins, the conformational changes, which lead to activation of the protein, are not understood. We reveal cryo electron microscopy structures of the complete phytochrome from Deinoccocus radiodurans in its resting and photoactivated states at 3.6 Å and 3.5 Å resolution, respectively. Upon photoactivation, the photosensory core module hardly changes its ter…
Sequential conformational transitions and α-helical supercoiling regulate a sensor histidine kinase
2017
Sensor histidine kinases are central to sensing in bacteria and in plants. They usually contain sensor, linker, and kinase modules and the structure of many of these components is known. However, it is unclear how the kinase module is structurally regulated. Here, we use nano- to millisecond time-resolved X-ray scattering to visualize the solution structural changes that occur when the light-sensitive model histidine kinase YF1 is activated by blue light. We find that the coiled coil linker and the attached histidine kinase domains undergo a left handed rotation within microseconds. In a much slower second step, the kinase domains rearrange internally. This structural mechanism presents a t…
The Low Barrier Hydrogen Bond in the Photoactive Yellow Protein: A Vacuum Artifact Absent in the Crystal and Solution
2016
Journal of the American Chemical Society 138(51), 16620 - 16631 (2016). doi:10.1021/jacs.6b05609
The Minor Capsid Protein VP11 of Thermophilic Bacteriophage P23-77 Facilitates Virus Assembly by Using Lipid-Protein Interactions
2015
ABSTRACT Thermus thermophilus bacteriophage P23-77 is the type member of a new virus family of icosahedral, tailless, inner-membrane-containing double-stranded DNA (dsDNA) viruses infecting thermophilic bacteria and halophilic archaea. The viruses have a unique capsid architecture consisting of two major capsid proteins assembled in various building blocks. We analyzed the function of the minor capsid protein VP11, which is the third known capsid component in bacteriophage P23-77. Our findings show that VP11 is a dynamically elongated dimer with a predominantly α-helical secondary structure and high thermal stability. The high proportion of basic amino acids in the protein enables electrost…
Comparative trial between the use of amoxicillin and amoxicillin clavulanate in the removal of third molars
2014
Objectives: The purpose of this study was to compare the use of amoxicillin (1g) vs amoxicillin and clavulanate (875/125mg) after extraction of retained third molars for prevention of infectious complications. Study Design: The study involved 546 patients attending for removal a retained third molar and divided in to two groups: Group 1 - amoxicillin and clavunate (875/125mg) group (n=257) and Group 2 - amoxicillin (1g) group (n=289). All patients were recalled for investigating the possibility of infection, presence of diarrhea and further analgesic intake. Results: From a total of 546 patients, the frequency of infection was 1.4%, without no statistically differences be - tween the two gr…
Diversity of Lactobacillus species in deep carious lesions of primary molars
2010
AIM: This was to determine the prevalence of Lactobacilli (LB) species in different stages of caries progression and are considered as secondary invaders of existing carious lesions and specialists for caries progression. METHODS: Carious dentine samples were collected from 70 primary molars (M) during step-wise (S1, S2: n = 35 M) or one-step (O1: n = 35 M) caries treatment and after 11 months of temporary restorations (S3, O2). LB were identified by selected physiological and biochemical characteristics, ratio of lactic acid isomers, electrophoretic mobilities of lactic acid dehydrogenases, and shotgun mass mapping by MALDI mass spectrometry. RESULTS: LB were isolated from 46% of soft dent…
Penetration of Streptococcus sobrinus and Streptococcus sanguinis into dental enamel.
2015
Abstract The aim of this pilot study was to assess the difference in virulence of acidogenic and aciduric oral streptococci in an in vitro caries model using their penetration depths into dental enamel. 30 caries-free extracted molars from 11- to 16-year-olds were cleaned ultrasonically for 1 min with de-ionized water and, after air-drying, embedded in epoxy resin. After 8-h of setting at room temperature, the specimens were ground on the buccal side with SiC-paper 1200 (particle size 13–16 μm). Enamel was removed in circular areas sized 3 mm in diameter; the mean depth of removed enamel was 230 ± 60 μm. 15 specimens each were incubated anaerobically under standardized conditions with 24 h-…
Antibacterial suture vs silk for the surgical removal of impacted lower third molars. A randomized clinical study.
2015
Background The aim of this study was to evaluate the clinical and microbiological impact of an antibacterial suture (Monocryl® Plus) in the surgical removal of I3M. Material and Methods A “split-mouth”, prospective pilot clinical study was designed involving 20 patients programmed for the surgical removal of I3M. Each side was randomly sutured with Monocryl® Plus or silk suture and removed for microbiological study 72 hours and 7 days after surgery. Presence of SSI, wound bleeding and the degree of discomfort associated with each type of suture material (scored by means of a visual analog scale) were evaluated. The level of contamination of each material was observed under the scanning elec…