Amino acid synthesis is necessary for tomato root colonization by Pseudomonas fluorescens strain WCS365

Microbial Biotechnolog

The Response of Lactococcus lactis to Membrane Protein Production

Background: The biogenesis of membrane proteins is more complex than that of water-soluble proteins, and recombinant expression of membrane proteins in functional form and in amounts high enough for structural and functional studies is often problematic. To better engineer cells towards efficient protein production, we set out to understand and compare the cellular consequences of the overproduction of both classes of proteins in Lactococcus lactis, employing a combined proteomics and transcriptomics approach. Methodology and Findings: Highly overproduced and poorly expressed membrane proteins both resulted in severe growth defects, whereas amplified levels of a soluble substrate receptor had no effect. In addition, membrane protein overproduction evoked a general stress response (upregulation of various chaperones and proteases), which is probably due to accumulation of misfolded protein. Notably, upon the expression of membrane proteins a cell envelope stress response, controlled by the two-component regulatory CesSR system, was observed. Conclusions: The physiological response of L. lactis to the overproduction of several membrane proteins was determined and compared to that of a soluble protein, thus offering better understanding of the bottlenecks related to membrane protein production and valuable knowledge for subsequent strain engineering.

Oxidative protein labeling in mass-spectrometry-based proteomics

Oxidation of proteins and peptides is a common phenomenon, and can be employed as a labeling technique for mass-spectrometry-based proteomics. Nonspecific oxidative labeling methods can modify almost any amino acid residue in a protein or only surface-exposed regions. Specific agents may label reactive functional groups in amino acids, primarily cysteine, methionine, tyrosine, and tryptophan. Nonspecific radical intermediates (reactive oxygen, nitrogen, or halogen species) can be produced by chemical, photochemical, electrochemical, or enzymatic methods. More targeted oxidation can be achieved by chemical reagents but also by direct electrochemical oxidation, which opens the way to instrumental labeling methods. Oxidative labeling of amino acids in the context of liquid chromatography(LC)–mass spectrometry (MS) based proteomics allows for differential LC separation, improved MS ionization, and label-specific fragmentation and detection. Oxidation of proteins can create new reactive groups which are useful for secondary, more conventional derivatization reactions with, e.g., fluorescent labels. This review summarizes reactions of oxidizing agents with peptides and proteins, the corresponding methodologies and instrumentation, and the major, innovative applications of oxidative protein labeling described in selected literature from the last decade

The prevalence of mild cognitive impairment in diverse geographical and ethnocultural regions: The COSMIC Collaboration

Background Changes in criteria and differences in populations studied and methodology have produced a wide range of prevalence estimates for mild cognitive impairment (MCI). Methods Uniform criteria were applied to harmonized data from 11 studies from USA, Europe, Asia and Australia, and MCI prevalence estimates determined using three separate definitions of cognitive impairment. Results The published range of MCI prevalence estimates was 5.0%-36.7%. This was reduced with all cognitive impairment definitions: performance in the bottom 6.681% (3.2%-10.8%); Clinical Dementia Rating of 0.5 (1.8%-14.9%); Mini-Mental State Examination score of 24-27 (2.1%-20.7%). Prevalences using the first definition were 5.9% overall, and increased with age (P < .001) but were unaffected by sex or the main races/ethnicities investigated (Whites and Chinese). Not completing high school increased the likelihood of MCI (P = .01). Conclusion Applying uniform criteria to harmonized data greatly reduced the variation in MCI prevalence internationally

Efficient and Selective Chemical Labeling of Electrochemically Generated Peptides Based on Spirolactone Chemistry

Contains fulltext : 161993.pdf (publisher's version ) (Open Access

Kommunikation och definition av konsistensanpassad kost i vården

En betydande risk för att utveckla undernäring finns vid förekomst av dysfagi, det vill säga ätsvårigheter. Genom att anpassa kostens konsistens kan dock intaget av mat och dryck under-lättas och även möjligheten att tillgodose näringsbehov. Vilken kostkonsistens som serveras bör därmed betraktas som en medicinsk åtgärd och ordination. En förutsättning för att vårdta-garen erhåller rätt kostkonsistens är att kommunikationen mellan olika vårdgivare är väl fun-gerande och att kostansvariga är införstådda med vilken kostkonsistens som vårdtagaren ska inta. Ytterliggare krav på god kommunikation ställs då terminologin för konsistensanpassad kost varierar. Föreliggande studie utgör en del av Vinnova-projektet ”System och definition av livsmedelskonsistenser för nutritionsbehandling vid dysfagi”. Syftet var att undersöka hur informationsöverföring av konsistensanpassad kost fungerar mellan personal inom olika vård- och omsorgsformer samt vid utskrivning/flytt av vårdtagare med tugg- och sväljsvårigheter. Resultatet baseras på en intervjustudie där åtta vårdtagare som intagit konsistensanpassad kost följts i samband med utskrivning från sjukhus till aktuell boendeform. Totalt genomfördes 22 intervjuer med vårdtagare/anhörig, vårdpersonal och kökspersonal. Resultatet visade att do-kumentation av kostkonsistens fanns men att tolkningen och informationsöverföringen av denna kunde brista i vårdkedjan. Bakomliggande orsak var förvirring kring skiftande konsi-stensbenämningar och benämningarnas innebörd. För att säkerställa vårdtagarens behov av en individuellt anpassad kostkonsistens krävs fortsatt arbete mot tydliga riktlinjer och gemen-samma konsistensdefinitioner. Därtill behövs fler måltidslösningar för vårdtagare som skrivs ut till ordinärt boende utan kommunala insatser, men med ett fortsatt behov av konsistensan-passad kost

Functional and Structural Characterization of an Unusual Cofactor-Independent Oxygenase

The vast majority of characterized oxygenases use bound cofactors to activate molecular oxygen to carry out oxidation chemistry. Here, we show that an enzyme of unknown activity, RhCC from Rhodococcus jostii RHA1, functions as an oxygenase, using 4-hydroxyphenylenolpyruvate as a substrate. This unique and complex reaction yields 3-hydroxy-3-(4-hydroxyphenyl)-pyruvate, 4-hydroxybenzaldehyde, and oxalic acid as major products. Incubations with H2(18)O, (18)O2, and a substrate analogue suggest that this enzymatic oxygenation reaction likely involves a peroxide anion intermediate. Analysis of sequence similarity and the crystal structure of RhCC (solved at 1.78 Å resolution) reveal that this enzyme belongs to the tautomerase superfamily. Members of this superfamily typically catalyze tautomerization, dehalogenation, or decarboxylation reactions rather than oxygenation reactions. The structure shows the absence of cofactors, establishing RhCC as a rare example of a redox-metal- and coenzyme-free oxygenase. This sets the stage to study the mechanistic details of cofactor-independent oxygen activation in the unusual context of the tautomerase superfamily