40 research outputs found

    Time-Lapse Microscopy of Streptomyces coelicolor Growth and Sporulation ▿ †

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    Bacteria from the genus Streptomyces are among the most complex of all prokaryotes; not only do they grow as a complex mycelium, they also differentiate to form aerial hyphae before developing further to form spore chains. This developmental heterogeneity of streptomycete microcolonies makes studying the dynamic processes that contribute to growth and development a challenging procedure. As a result, in order to study the mechanisms that underpin streptomycete growth, we have developed a system for studying hyphal extension, protein trafficking, and sporulation by time-lapse microscopy. Through the use of time-lapse microscopy we have demonstrated that Streptomyces coelicolor germ tubes undergo a temporary arrest in their growth when in close proximity to sibling extension sites. Following germination, in this system, hyphae extended at a rate of ∼20 μm h−1, which was not significantly different from the rate at which the apical ring of the cytokinetic protein FtsZ progressed along extending hyphae through a spiraling movement. Although we were able to generate movies for streptomycete sporulation, we were unable to do so for either the erection of aerial hyphae or the early stages of sporulation. Despite this, it was possible to demonstrate an arrest of aerial hyphal development that we suggest is through the depolymerization of FtsZ-enhanced green fluorescent protein (GFP). Consequently, the imaging system reported here provides a system that allows the dynamic movement of GFP-tagged proteins involved in growth and development of S. coelicolor to be tracked and their role in cytokinesis to be characterized during the streptomycete life cycle

    Replisome Trafficking in Growing Vegetative Hyphae of Streptomyces coelicolor A3(2) ▿ #

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    We observed movies of replisome trafficking during Streptomyces coelicolor growth. A replisome(s) in the spore served as a replication center(s) until hyphae reached a certain length, when a tip-proximal replisome formed and moved at a fixed distance behind the tip at a speed equivalent to the extension rate of the tip

    Clinical Assessment of the Effects of Low-Level Laser Therapy on Coronally Advanced Flap Procedure in the Management of Isolated Gingival Recession

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    The aim of this randomized, controlled split-mouth clinical trial was to assess the effect of LLLT on wound healing after modified coronally advanced flap (MCAF) procedure for treatment of isolated recession-type defects. Fifteen patients with isolated bilaterally symmetrical gingival recessions (Miller’s Class I or Class II, or a combination of both) were enrolled in this study. After a modified, coronally advanced flap technique was implemented, a diode laser (810 nm) with a power of 120 mW irradiated the inner surface of the flap and the outer surface of the flap (low-level laser therapy—LLLT) after suturing for 5 min. This was repeated for the following four consecutive days. Descriptive statistics, a Kruskal–Wallis test and a Mann–Whitney test were performed to analyze the data. A p-value of less than 0.05 was considered statistically significant. The mean recession depth decreased from 3.33 ± 0.9 mm (baseline) to 0.2 ± 0.3 mm (3 months) and 0.4 ± 0.2 mm (6 months) in the test group. The mean recession width decreased from 3.8 ± 0.7 mm (baseline) to 0.2 ± 0.3 mm (3 months) and 0.5 ± 0.3 mm (6 months) in the test group. Due to minimal pain and discomfort, patient acceptability was quite high

    Regeneration of Intrabony Defects with Nano Hydroxyapatite Graft, Derived from Eggshell along with Periosteum as Barrier Membrane under Magnification—An Interventional Study

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    Intrabony defects can be treated by various approaches. Use of GTR along with bone grafts is said to enhance the outcome. The periosteum has been claimed to increase the regeneration. The egg-shell-derived nano hydroxyapatite (EnHA) has shown a scope as alloplastic graft. Thus, the following study was undertaken to combine the periosteal pedicle along with EnHA for the treatment of intrabony defects under magnification to achieve optimal bone regeneration. A total of 21 patients, having intrabony defects with ≥6 mm probing depth (PD) and two or three wall defects as detected on CBCT, satisfying inclusion criteria were enrolled. The sites were randomly allocated as Group A, B and C (n = 7). The following parameters, defect density and defect fill in CBCT (at baseline and 6 months), PPD, RAL, Plaque index (PI), Gingival index (GI) and Gingival Bleeding Index (GBI) were recorded at baseline, 1, 3 and 6 months. p < 0.05 is considered as statistically significant. Bone density and bone fill values were found to be much higher in pedicle with EnHA and EnHA alone group and the values showed statistically significant results. The current clinical research showed that periosteal pedicle along with EnHA and EnHA as stand-alone therapy gave superior results compared to OFD alone, which is an innovative and feasible treatment option

    Alterations of the CIB2 calcium- and integrin-binding protein cause Usher syndrome type 1J and nonsyndromic deafness DFNB48

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    Sensorineural hearing loss is genetically heterogeneous. Here we report that mutations in CIB2, encoding a Ca(2+)- and integrin-binding protein, are associated with nonsyndromic deafness (DFNB48) and Usher syndrome type 1J (USH1J). There is one mutation of CIB2 that is a prevalent cause of DFNB48 deafness in Pakistan; other CIB2 mutations contribute to deafness elsewhere in the world. In rodents, CIB2 is localized in the mechanosensory stereocilia of inner ear hair cells and in retinal photoreceptor and pigmented epithelium cells. Consistent with molecular modeling predictions of Ca(2+) binding, CIB2 significantly decreased the ATP-induced Ca(2+) responses in heterologous cells, while DFNB48 mutations altered CIB2 effects on Ca(2+) responses. Furthermore, in zebrafish and Drosophila, CIB2 is essential for the function and proper development of hair cells and retinal photoreceptor cells. We show that CIB2 is a new member of the vertebrate Usher interactome

    Analyses of pig genomes provide insight into porcine demography and evolution

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    For 10,000 years pigs and humans have shared a close and complex relationship. From domestication to modern breeding practices, humans have shaped the genomes of domestic pigs. Here we present the assembly and analysis of the genome sequence of a female domestic Duroc pig (Sus scrofa) and a comparison with the genomes of wild and domestic pigs from Europe and Asia. Wild pigs emerged in South East Asia and subsequently spread across Eurasia. Our results reveal a deep phylogenetic split between European and Asian wild boars ~1 million years ago, and a selective sweep analysis indicates selection on genes involved in RNA processing and regulation. Genes associated with immune response and olfaction exhibit fast evolution. Pigs have the largest repertoire of functional olfactory receptor genes, reflecting the importance of smell in this scavenging animal. The pig genome sequence provides an important resource for further improvements of this important livestock species, and our identification of many putative disease-causing variants extends the potential of the pig as a biomedical model.This is an article from Nature 491 (2012): 393, doi:10.1038/nature11622. Posted with permission.</p

    Performance of the ALICE Experiment at the CERN LHC

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    ALICE is the heavy-ion experiment at the CERN Large Hadron Collider. The experiment continuously took data during the first physics campaign of the machine from fall 2009 until early 2013, using proton and lead-ion beams. In this paper we describe the running environment and the data handling procedures, and discuss the performance of the ALICE detectors and analysis methods for various physics observables.ALICE is the heavy-ion experiment at the CERN Large Hadron Collider. The experiment continuously took data during the first physics campaign of the machine from fall 2009 until early 2013, using proton and lead-ion beams. In this paper we describe the running environment and the data handling procedures, and discuss the performance of the ALICE detectors and analysis methods for various physics observables.ALICE is the heavy-ion experiment at the CERN Large Hadron Collider. The experiment continuously took data during the first physics campaign of the machine from fall 2009 until early 2013, using proton and lead-ion beams. In this paper we describe the running environment and the data handling procedures, and discuss the performance of the ALICE detectors and analysis methods for various physics observables

    Multiplicity dependence of the average transverse momentum in pp, p-Pb, and Pb-Pb collisions at the LHC

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    The average transverse momentum versus the charged-particle multiplicity NchN_{ch} was measured in p-Pb collisions at a collision energy per nucleon-nucleon pair sNN\sqrt{s_{NN}} = 5.02 TeV and in pp collisions at collision energies of s\sqrt{s} = 0.9, 2.76, and 7 Tev in the kinematic range 0.15 with NchN_{ch} is observed, which is much stronger than that measured in Pb-Pb collisions. For pp collisions, this could be attributed, within a model of hadronizing strings, to multiple-parton interactions and to a final-state color reconnection mechanism. The data in p-Pb and Pb-Pb collisions cannot be described by an incoherent superposition of nucleon-nucleon collisions and pose a challenge to most of the event generators
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