Ankersennordentoft8803

surfaces. Root exudates are complex chemical mixtures that are spatially and temporally dynamic. Identifying the exact chemical(s) that mediate recruitment of soil bacteria to specific regions of the roots is thus challenging. Here, we connect patterns of bacterial chemotaxis responses and sensing by chemoreceptors to chemicals found in root exudates gradients and identify key chemical signals that shape root surface colonization in different plants and regions of the roots.The thermotolerant yeast Ogataea parapolymorpha (formerly Hansenula polymorpha) is an industrially relevant production host that exhibits a fully respiratory sugar metabolism in aerobic batch cultures. NADH-derived electrons can enter its mitochondrial respiratory chain either via a proton-translocating Complex I NADH-dehydrogenase or via three putative alternative NADH dehydrogenases. This respiratory entry point affects the amount of ATP produced per NADH/O2 consumed and therefore impacts the maximum yield of biomass and/or cellular products from a given amount of substrate. To investigate the physiological importance of Complex I, a wild-type O. parapolymorpha strain and a congenic Complex I-deficient mutant were grown on glucose in aerobic batch, chemostat and retentostat cultures in bioreactors. In batch cultures, both strains exhibited a fully respiratory metabolism and showed the same growth rate and biomass yield, indicating that, under these conditions, the contribution of NADH oxidation via Complex In aerobic industrial processes, suboptimal energy coupling results in reduced product yields on sugar, increased process costs for oxygen transfer, and volumetric productivity limitations due to limitations in gas transfer and cooling. This study provides insights into the contribution of mechanisms of respiratory energy coupling in the yeast cell factory Ogataea parapolymorpha under different growth conditions and provides a basis for rational improvement of energy coupling in yeast cell factories. Veliparib Analysis of energy metabolism of O. parapolymorpha at extremely low specific growth rates indicated that this yeast reduces its energy requirements for cellular maintenance under extreme energy limitation. Exploration of the mechanisms for this increased energetic efficiency may contribute to an optimization of the performance of industrial processes with slow-growing eukaryotic cell factories.Nisin A is a potent antimicrobial with potential as an alternative to traditional antibiotics, and a number of genetically modified variants have been created that target clinically relevant pathogens. In addition to antimicrobial activity, nisin auto-regulates its own production via a signal transduction pathway, a property that has been exploited in a protein expression system termed the Nisin Controlled Gene Expression (NICE) system. Although NICE has become one of the most popular protein expression systems, one drawback is that the inducer peptide, nisin A, also has inhibitory activity. It has already been demonstrated that the N-terminal region of nisin A contributes to antimicrobial activity and signal transduction properties, therefore, we conducted bioengineering of nisin at positions Pro9 and Gly10 within ring B to produce a bank of variants that could potentially be used as alternative induction peptides. One variant, designated nisin M, has threonines at positions 9 and 10 and retains induction capacity comparable to the wild type nisin A, while most of the antimicrobial activity is abolished. Further analysis confirmed that nisin M produces a mix of peptides as a result of different degrees of dehydration of the two threonines. We show that nisin M exhibits potential as a more suitable alternative to nisin A for the expression of proteins that may be difficult to express, or to produce proteins in strains that are sensitive to wild type nisin. Moreover, it may address the increasing demand by industry for optimization of peptide fermentations to increase yields or their production rate.Importance This study describes the generation of a nisin variant with superior characteristics for use in the NICE protein expression system. The variant, termed nisin M, retains an induction capacity comparable to the wild type nisin A but exhibits significantly reduced antimicrobial activity and can therefore be used at concentrations that are normally toxic to the expression host.In order to estimate herd-level prevalence of ESBL-/AmpC- and carbapenemase-producing commensal Escherichia coli in ruminants in the Basque Country (Northern Spain), a cross-sectional survey was conducted in 2014-2016 in 300 herds using selective isolation. ESBL-/AmpC-producing E. coli were isolated in 32.9% of dairy cattle herds, 9.6% of beef cattle herds and 7.0% of sheep flocks. No carbapenemase-producing E. coli were isolated. Phenotypic antimicrobial susceptibility determined by broth microdilution using EUCAST epidemiological cut-off values identified widespread co-resistance to extended spectrum cephalosporins and other antimicrobials (110/135 isolates), particularly tetracycline, sulfamethoxazole, trimethoprim, and ciprofloxacin. All isolates were susceptible to tigecycline, imipenem, meropenem and colistin. The genome of 66 isolates was sequenced using Illumina NovaSeq6000 and screened for antimicrobial resistance determinants against ResFinder and PointFinder. Plasmid/chromosomal location of resistarobial resistance determinants in humans and food-producing animals, becoming a concern for animal and public health. This study provided an insight into the prevalence of cefotaxime-resistant E. coli in cattle and sheep in the Basque Country and the associated genetic determinants of antimicrobial resistance. These constituted an important contribution to the limited repository of such data for cattle in the region and for sheep worldwide. Antimicrobial susceptibility testing by phenotypic and molecular methods is key in surveillance programs to enhance early detection of resistance development, monitor resistance trends and provide guidance to clinicians in selecting the adequate therapy.Pyridine and its derivatives constitute majority of heterocyclic aromatic compounds that occur largely as a result of human activities and contribute to the environmental pollution. It is known, that they can be degraded by various bacteria in the environment, however, the degradation of unsubstituted pyridine has not yet been completely resolved. In this study we present data on the pyridine catabolic pathway in Arthrobacter sp. 68b at the level of genes, enzymes and metabolites. The pyr genes cluster, responsible for degradation of pyridine, was identified in a catabolic plasmid p2MP. The pathway of pyridine metabolism consisted of four enzymatic steps and ended by formation of succinic acid. The first step in the degradation of pyridine proceeds through a direct ring cleavage catalyzed by a two-component flavin-dependent monooxygenase system, encoded by pyrA and pyrE genes. The genes pyrB, pyrC, and pyrD were found to encode (Z)-N-(4-oxobut-1-enyl)formamide dehydrogenase, amidohydrolase, and succinate semialdehyde dehydrogenase, respectively.