Post-translational modification of therapeutic peptides by NisB, the dehydratase of the lantibiotic nisin

Post-translationally introduced dehydroamino acids often play an important role in the activity and receptor specificity of biologically active peptides. In addition, a dehydroamino acid can be coupled to a cysteine to yield a cyclized peptide with increased biostability and resistance against proteolytic degradation and/or modified specificity. The lantibiotic nisin is an antimicrobial peptide produced by Lactococcus lactis. Its post-translational enzymatic modification involves NisB-mediated dehydration of serines and threonines and NisC-catalyzed coupling of cysteines to dehydroresidues, followed by NisT-mediated secretion. Here, we demonstrate that a L. lactis strain containing the nisBTC genes effectively dehydrates and secretes a wide range of medically relevant nonlantibiotic peptides among which variants of adrenocorticotropic hormone, vasopressin, an inhibitor of tripeptidyl peptidase II, enkephalin, luteinizing hormone-releasing hormone, angiotensin, and erythropoietin. For most of these peptides, ring formation was demonstrated. These data show that lantibiotic enzymes can be applied for the modification of peptides, thereby enabling the biotechnological production of dehydroresidue-containing and/or thioether-bridged therapeutic peptides with enhanced stability and/or modulated activities.</p

De Novo Peroxisome Biogenesis in Penicillium Chrysogenum Is Not Dependent on the Pex11 Family Members or Pex16

We have analyzed the role of the three members of the Pex11 protein family in peroxisome formation in the filamentous fungus Penicillium chrysogenum. Two of these, Pex11 and Pex11C, are components of the peroxisomal membrane, while Pex11B is present at the endoplasmic reticulum. We show that Pex11 is a major factor involved in peroxisome proliferation. We also demonstrate that P. chrysogenum cells deleted for known peroxisome fission factors (all Pex11 family proteins and Vps1) still contain peroxisomes. Interestingly, we find that, unlike in mammals, Pex16 is not essential for peroxisome biogenesis in P. chrysogenum, as partially functional peroxisomes are present in a pex16 deletion strain. We also show that Pex16 is not involved in de novo biogenesis of peroxisomes, as peroxisomes were still present in quadruple Δpex11 Δpex11B Δpex11C Δpex16 mutant cells. By contrast, pex3 deletion in P. chrysogenum led to cells devoid of peroxisomes, suggesting that Pex3 may function independently of Pex16. Finally, we demonstrate that the presence of intact peroxisomes is important for the efficiency of ß-lactam antibiotics production by P. chrysogenum. Remarkably, distinct from earlier results with low penicillin producing laboratory strains, upregulation of peroxisome numbers in a high producing P. chrysogenum strain had no significant effect on penicillin production

Symbolic Processing Of Poisson Series On A Hypercube Parallel Computer

In this report parallelization of a special-purpose computer algebra system, operating on Poisson series, is considered. The implementations dealing with parallelism on different levels have been performed on an nCUBE2 parallel computer. Application test problems in this work concern the computation of normal forms of ODEs. Algorithmical details and performance results (in terms of speed-up and efficiency) are presented. Keywords: computer algebra, formula manipulation, Poisson series, normal form of ODEs, parallel processing, hypercubes 1 Introduction Computer algebra algorithms often require a lot of computing time; it is therefore an important issue to try to parallelize such algorithms. We describe here the parallelization of a special purpose computer algebra system on an nCUBE2 parallel computer. The main purpose of this report is to show that parallelization can be implemented at the level of the elementary operations of the computer algebra system and more efficiently at the l..

Development and validation of the short Use of Creative Cognition Scale in studying

This paper reports the development and validation of a short Use of Creative Cognition Scale in Studying (UCCS) that was inspired by the Cognitive Processes Associated with Creativity (CPAC) scale. In Study 1, items from two of the six subscales of the CPAC were excluded due to conceptual and psychometric issues to create a 21-item CPAC scale, which was administered to 517 university students. Exploratory factor analysis revealed that the 21-item CPAC scale is unidimensional. Five items were selected to create the new unidimensional UCCS. In Study 2, 696 students completed the UCCS and a set of scales measuring related constructs. Confirmatory factor analysis corroborated the unidimensional structure of the scale. The scale correlated positively with measures of flow, trait intrinsic motivation, adaptive metacognitive traits and positive affect, it correlated negatively with negative affect, and it did not correlate with core maladaptive metacognitive traits. The findings indicate that the scale is a valid and reliable tool for research and monitoring

Peroxisomes Are Required for Efficient Penicillin Biosynthesis in Penicillium chrysogenum▿ †

In the fungus Penicillium chrysogenum, penicillin (PEN) production is compartmentalized in the cytosol and in peroxisomes. Here we show that intact peroxisomes that contain the two final enzymes of PEN biosynthesis, acyl coenzyme A (CoA):6-amino penicillanic acid acyltransferase (AT) as well as the side-chain precursor activation enzyme phenylacetyl CoA ligase (PCL), are crucial for efficient PEN synthesis. Moreover, increasing PEN titers are associated with increasing peroxisome numbers. However, not all conditions that result in enhanced peroxisome numbers simultaneously stimulate PEN production. We find that conditions that lead to peroxisome proliferation but simultaneously interfere with the normal physiology of the cell may be detrimental to antibiotic production. We furthermore show that peroxisomes develop in germinating conidiospores from reticule-like structures. During subsequent hyphal growth, peroxisome proliferation occurs at the tip of the growing hyphae, after which the organelles are distributed over newly formed subapical cells. We observed that the organelle proliferation machinery requires the dynamin-like protein Dnm1

The Penicillium chrysogenum aclA gene encodes a broad-substrate-specificity acyl-coenzyme A ligase involved in activation of adipic acid, a side-chain precursor for cephem antibiotics

Activation of the cephalosporin side-chain precursor to the corresponding CoA-thioester is an essential step for its incorporation into the β-lactam backbone. To identify an acyl-CoA ligase involved in activation of adipate, we searched in the genome database of Penicillium chrysogenum for putative structural genes encoding acyl-CoA ligases. Chemostat-based transcriptome analysis was used to identify the one presenting the highest expression level when cells were grown in the presence of adipate. Deletion of the gene renamed aclA, led to a 32% decreased specific rate of adipate consumption and a threefold reduction of adipoyl-6-aminopenicillanic acid levels, but did not affect penicillin V production. After overexpression in Escherichia coli, the purified protein was shown to have a broad substrate range including adipate. Finally, protein-fusion with cyan-fluorescent protein showed co-localization with microbody-borne acyl-transferase. Identification and functional characterization of aclA may aid in developing future metabolic engineering strategies for improving the production of different cephalosporins.

Educação de pacientes e familiares para a segurança do paciente : registros de prontuários em internação pediátrica

After kidney transplantation, decreased graft survival is seen in grafts from brain dead (BD) donors compared with living donors. This might result partly from a progressive nonspecific inflammation in the graft. In this study, we focused on the effects of BD on inflammatory response (adhesion molecules, leukocyte invasion, gene expression) and stress-related heat shock proteins in the human kidney. Research outcomes and clinical donor parameters were then linked to outcome data after transplantation. Kidney biopsy specimens and serum were obtained during organ retrieval from BD and living organ donor controls. Immunohistochemistry and semiquantitative reverse transcriptase-polymerase chain reaction were performed on the biopsy specimens. Clinical and laboratory parameters from BD donors were recorded and connected to outcome data of the recipients of the kidneys studied. After brain death, immunohistochemistry showed an increase of E-selectin (P <0.01) and interstitial leukocyte invasion (P <0.05) compared with controls. Also, reverse transcriptase-polymerase chain reaction showed a threefold increased heme oxygenase-1 (P <0.05) and Hsp70 (P <0.01) gene expression after BD. Levels of monocyte chemotactic protein-1 and transforming growth factor-beta were twice as high after brain death but did not reach significance. Transplantation outcome was influenced by several donor variables: positively most notably by donor treatment with desmopressin and negatively by high serum urea levels during brain death and by high intercellular adhesion molecule and vascular cell adhesion molecule expression in the kidney. Heme oxygenase-1 proved to have a protective function, but only in kidneys from living donors. The presence of interstitial leukocytes and the early adhesion molecule E-selectin in BD donor kidneys indicates an early-phase inflammatory process during organ retrieval. Elevated levels of monocyte chemotactic protein-1 and transforming growth factor-beta suggest a role for monocytes/macrophages in this phase. We suggest that BD causes a stress-related response against which protective heat shock proteins are formed in the future graft. This stress response may be too severe to be fully counteracted by elevated heat shock proteins. Which systemic and/or local factors trigger brain death-related graft injury is currently under investigatio