Intermediate filament-like proteins in bacteria and a cytoskeletal function in Streptomyces

Actin and tubulin cytoskeletons are conserved and widespread in bacteria. A strikingly intermediate filament (IF)-like cytoskeleton, composed of crescentin, is also present in Caulobacter crescentus and determines its specific cell shape. However, the broader significance of this finding remained obscure, because crescentin appeared to be unique to Caulobacter. Here we demonstrate that IF-like function is probably a more widespread phenomenon in bacteria. First, we show that 21 genomes of 26 phylogenetically diverse species encoded uncharacterized proteins with a central segmented coiled coil rod domain, which we regarded as a key structural feature of IF proteins and crescentin. Experimental studies of three in silico predicted candidates from Mycobacterium and other actinomycetes revealed a common IF-like property to spontaneously assemble into filaments in vitro. Furthermore, the IF-like protein FilP formed cytoskeletal structures in the model actinomycete Streptomyces coelicolor and was needed for normal growth and morphogenesis. Atomic force microscopy of living cells revealed that the FilP cytoskeleton contributed to mechanical fitness of the hyphae, thus closely resembling the function of metazoan IF. Together, the bioinformatic and experimental data suggest that an IF-like protein architecture is a versatile design that is generally present in bacteria and utilized to perform diverse cytoskeletal tasks

Roles of curli, cellulose and BapA in Salmonella biofilm morphology studied by atomic force microscopy

<p>Abstract</p> <p>Background</p> <p>Curli, cellulose and the cell surface protein BapA are matrix components in <it>Salmonella </it>biofilms. In this study we have investigated the roles of these components for the morphology of bacteria grown as colonies on agar plates and within a biofilm on submerged mica surfaces by applying atomic force microscopy (AFM) and light microscopy.</p> <p>Results</p> <p>AFM imaging was performed on colonies of <it>Salmonella </it>Typhimurium grown on agar plates for 24 h and on biofilms grown for 4, 8, 16 or 24 h on mica slides submerged in standing cultures. Our data show that in the wild type curli were visible as extracellular material on and between the cells and as fimbrial structures at the edges of biofilms grown for 16 h and 24 h. In contrast to the wild type, which formed a three-dimensional biofilm within 24 h, a curli mutant and a strain mutated in the global regulator CsgD were severely impaired in biofilm formation. A mutant in cellulose production retained some capability to form cell aggregates, but not a confluent biofilm. Extracellular matrix was observed in this mutant to almost the same extent as in the wild type. Overexpression of CsgD led to a much thicker and a more rapidly growing biofilm. Disruption of BapA altered neither colony and biofilm morphology nor the ability to form a biofilm within 24 h on the submerged surfaces. Besides curli, the expression of flagella and pili as well as changes in cell shape and cell size could be monitored in the growing biofilms.</p> <p>Conclusion</p> <p>Our work demonstrates that atomic force microscopy can efficiently be used as a tool to monitor the morphology of bacteria grown as colonies on agar plates or within biofilms formed in a liquid at high resolution.</p

Ordered coalescence of nano-crystals in alkaline niobate ceramics with high remanent polarization

Lead-free alkali niobates Na0.5K0.5NbO3 (NKN) ceramics, with significantly enhanced ferroelectric remanent polarization (Pr), were prepared using Spark Plasma Sintering (SPS). Three types of boundaries were observed in the ceramics, being grain boundaries between faceted grains, domain boundaries that separate ferroelectric domains inside individual grains, and nanoscale sub-grain boundaries that reveal the nano-scale mosaicity of individual grains. Part of the sub-grain boundaries were from initial powder particles. The other sub-grain boundaries were built by ordered coalescence of nano-crystals during rapid SPS process. It was worthwhile to emphasize that the ordered coalescence of nano-crystals in bulk ceramics during sintering takes place and completes within minutes. These sub-grain features would disappear at higher temperature by long time sintering. Rapid Spark Plasma Sintering allowed us to capture this transient microstructure. The significantly enhanced ferroelectric Pr of NKN was attributed to nanoscale sub-boundaries, which stimulated the dynamics of ferroelectric domain formation and switching

Pattern Shape Control for Heat Treatment Purification of Electron-Beam-Induced Deposition of Gold from the Me₂Au(acac) Precursor

Gold structures can be created in a scanning electron microscope (SEM) from the Me₂Au­(acac) precursor by direct writing with the electron beam. The as-deposited purity is usually poor, and a common purification approach is a post-annealing step that indeed is effective but also induces a volume reduction because of carbon loss and an undesirable reconfiguration of the gold structure, resulting in the loss of the original shape. We studied the shape change as a result of such purification, and to minimize this effect, the application of a tantalum and chromium buffer layer was investigated. These buffer materials are well-known for their good adhesion properties. We confirm by dedicated SEM, atomic force microscopy (AFM), and transmission electron microscopy (TEM) analysis that, for the creation of a uniform Au structure, tantalum is a better buffer layer material than chromium. Post-annealing of the Au electron-beam-induced deposition (EBID) patterns for 1 h at 600 °C in air resulted in a dramatic purity increase (from 8–12 atomic % Au to above 92 atomic % Au). The uncovered part of the tantalum layer can be easily etched away, resulting in a well-defined, high-purity, gold structure

Process considerations for layer-by-layer 3D patterning of silicon, using ion implantation, silicon deposition, and selective silicon etching

The authors study suitable process parameters, and the resulting pattern formation, in additive layer-by-layer fabrication of arbitrarily shaped three-dimensional (3D) silicon (Si) micro- and nanostructures. The layer-by-layer fabrication process investigated is based on alternating steps of chemical vapor deposition of Si and local implantation of gallium ions by focused ion beam writing. In a final step, the defined 3D structures are formed by etching the Si in potassium hydroxide, where the ion implantation provides the etching selectivity.QC 20121129M&M

Music Therapy in Practice of Childcare

A N O T Ā C I J A Bakalaura darba “ Mūzikas terapija bērnu aprūpes praksē” mērķis– iegūt papildus zināšanas un noskaidrot, mūzikas terapijas pasīvās formas izmantošanas efektivitāti perifērās vēnas kanilēšanas laikā jaunākā skolas vecuma bērniem. Mērķa sasniegšanai veikts pētījums, kura īstenošanai pielietota kombinētā pētniecības metode – daļēji strukturēta intervija un protokols ar mērījumiem bērniem. Pētījuma dalībnieki ir 20 jaunākie skolas vecuma pacienti, un 5 bērnu aprūpes māsas. Pētījumam izvirzītais jautājums- kas liecina par mūzikas terapijas metodes pielietošanas efektivitāti perifērās vēnas kanilēšanas laikā jaunākā skolas vecuma bērniem? Darbā izmantota H. Peplau (Hildegard E. Peplau 1909. – 1999.) māszinību aprūpes teorija, kuras pamatā ir starppersonu attiecību modelis. Pēc datu apkopošanas tika izdarīti secinājumi, no kuriem nozīmīgākais ir, ka mūzikas terapijas pasīvās metodes pielietošana perifērās vēnas kanilēšanas laikā jaunākā skolas vecuma bērniem ir emocionālo līdzsvaru veidojošs faktors, kas bērnos mazina trauksmi.Atslēgas vārdi: stress, trauksme, sāpes, bērni, mūzikas terapija.A N N O T A T I O N Bachelor thesis ''Music therapy in practice of childcare'' objective - to gain more knowledge and to find out about music therapy use of passive form efficiency in peripheral vascular system during cannulation to the youngest school-age children. To achieve the objective, a research has been done in which was used a combined research method - semi-structured interview and protocol with measurements to children. Research participants are 20 youngest school-age patients and 5 childcare nurses. The question raised to research - what indicates about the efficiency of music therapy method used in peripheral vascular system to the youngest school-age children? The author used in thesis is H. Peplau (Hildegard E. Peplau 1909. - 1999.) nursing care theory, based on the interpersonal relationship model. After data collection the most important conclusion is that music therapy passive method usage in peripheral vascular system during cannulation to the youngest school-age children have emotional balance formative factor in children that reduces anxiety. Key words: stress, anxiety, pain, children, music therapy

3D Free-Form Patterning of Silicon by Ion Implantation, Silicon Deposition, and Selective Silicon Etching

A method for additive layer-by-layer fabrication of arbitrarily shaped 3D silicon micro- and nanostructures is reported. The fabrication is based on alternating steps of chemical vapor deposition of silicon and local implantation of gallium ions by focused ion beam (FIB) writing. In a final step, the defined 3D structures are formed by etching the silicon in potassium hydroxide (KOH), in which the local ion implantation provides the etching selectivity. The method is demonstrated by fabricating 3D structures made of two and three silicon layers, including suspended beams that are 40 nm thick, 500 nm wide, and 4 μm long, and patterned lines that are 33 nm wide.QC 20120618</p

Layer-by-layer 3D printing of Si micro- and nanostructures by Si deposition, ion implantation and selective Si etching

In this paper we report a method for layer-by-layer printing of three-dimensional (3D) silicon (Si) micro- and nanostructures. This fabrication method is based on a sequence of alternating steps of chemical vapor deposition of Si and local implantation of gallium (Ga+) ions by focused ion beam (FIB) writing. The defined 3D structures are formed in a final step by selectively wet etching the non-implanted Si in potassium hydroxide (KOH). We demonstrate the viability of the method by fabricating 2 and 3-layer 3D Si structures, including suspended beams and patterned lines with dimensions on the nm-scale.QC 20130110M&M

Usability of E-health portal in the assessment of seniors

Bakalaura darba “E-veselības portāla lietojamība senioru vērtējumā” galvenais mērķis ir noskaidrot Eveseliba.gov.lv tīmekļa vietnes sadaļu, kurai var piekļūt autorizēti lietotāji, no lietojamības skatu punkta, senioru vidū no 60 līdz 69 gadiem. Pētījums tiek balstīts uz teorētisko modeli “Mijiedarbības trīs komponentu modeli” (The Interaction Triptych Model), kuru ir izstrādājuši divi teorētiķi: Giannis Taskonas(Giannis Tsakonas) un Kristos Papateodoru (Christos Papatheodorou). Tīmekļa vietnes analīze tiek veikta uz verbālā protokola pamata un modelī noteiktiem lietojamības kritērijiem.The goal of the bachelor’s thesis “Usability of E-health portal in the assessment of seniors” is to study the authorized section of Eveseliba.gov.lv website from a usability point of view by seniors aged 60 to 69. The study is based on the “Interaction Triptych Model”, which was developed by Giannis Tsakonas and the Christos Papatheodorou. Website analysis is performed on the basis of verbal protocol and usability criteria defined in the model

Topography AFM images of biofilms formed by UMR1 (wt), MAE52 (), MAE51 (), MAE14 (), MAE222 () and MAE619 () after growth for 24 hours on mica surfaces

<p><b>Copyright information:</b></p><p>Taken from "Roles of curli, cellulose and BapA in biofilm morphology studied by atomic force microscopy"</p><p>http://www.biomedcentral.com/1471-2180/7/70</p><p>BMC Microbiology 2007;7():70-70.</p><p>Published online 24 Jul 2007</p><p>PMCID:PMC1949822.</p><p></p