"Natürlich - der Mensch steht im Mittelpunkt!": zur organisationalen Funktion anthropologischer Präsuppositionen in der Personalsemantik moderner Organisationen

"In kaum einem gesellschaftlichen Kommunikationsbereich werden so viele anthropologische Grundannahmen über die menschliche Verfassung gemacht wie in der Personalsemantik moderner Organisationen. Der moderne Organisationsmensch ist plastisch, flexibel, form- und gestaltbar. Er kann, soll und muss als wertvolle Humanressource in seinen Möglichkeiten, Fähigkeiten und Fertigkeiten entwickelt und unternehmenskulturell gepflegt werden. In personalwirtschaftlichen Konzepten, die auf Veränderbarkeit, Plastizität und Perfektabilität des Organisationsmenschen zielen (Potentialanalysen, Coachings und Weiterbildungstrainings) werden organisationale Strukturen und Prozesse mit Vorstellungen über körperliche, kognitive und psycho-emotionale Fitness des Personals über den Lern- und den Leistungsbegriff miteinander verbunden. In den Idealvorstellungen dominiert heute nicht mehr die funktionalistisch auf Einzelaufgaben getrimmte Arbeitskraft, sondern die gesamte Persönlichkeit, die es zu Höchstleistung zu mobilisieren und motivieren gilt. Es herrscht ein - wie Niklas Luhmann formuliert - angeheiztes Interesse an Personen. Neben der Plastizitätsvorstellung stehen aber auch immer wieder Annahmen über das Unveränderbare, die Unberechenbarkeit und das Idiosynkratische von Individuen, in denen Konzepte wie Talent, Intuition und Begabung kursieren, die gerade nicht auf egalitäre Lernchancen, sondern auf in der personalen Umwelt der Organisation ungleich verteilte Leistungspotentiale abzielen. In diesem Segment soll und kann Beschäftigungsfähigkeit nicht komplett entwickelt, sondern muss sie schlicht vorausgesetzt werden. Es ist dann die Aufgabe des Recruiting, diese knappe Ressource verfügbar zu machen und die Querdenker, Neinsager, Abweichler und kreativen Köpfe für Führungspositionen zu gewinnen. Der Vortrag versucht eine Verbindung zwischen den Variationen in den anthropologischen Grundannahmen moderner Personalsemantik und Organisationsstrukturen aufzuzeigen. Die These des Verfassers ist, dass die zwei unterschiedlichen Semantiken - einmal geht es um Personal als veränderbare Entscheidungsprämisse, einmal als unveränderbare Entscheidungsprämisse - je nach organisationaler Strukturlage variiert werden und so auf die unterschiedliche organisationale Stellenstruktur reagieren. Für den großen Bereich der 'Normalarbeitskräfte' werden die Potential- und Lernsemantiken aktiviert. Bezogen auf die deutlich knapperen Führungspositionen wird hingegen die elitäre Semantik der Widerspenstigkeit und Idiosynkrasie hinzugezogen. Hier wird die Zone akzeptierter Abweichung erweitert und die Inklusionsbedingungen werden modifiziert." (Autorenreferat

Genetic tools for the investigation of Roseobacter clade bacteria

<p>Abstract</p> <p>Background</p> <p>The <it>Roseobacter </it>clade represents one of the most abundant, metabolically versatile and ecologically important bacterial groups found in marine habitats. A detailed molecular investigation of the regulatory and metabolic networks of these organisms is currently limited for many strains by missing suitable genetic tools.</p> <p>Results</p> <p>Conjugation and electroporation methods for the efficient and stable genetic transformation of selected <it>Roseobacter </it>clade bacteria including <it>Dinoroseobacter shibae</it>, <it>Oceanibulbus indolifex</it>, <it>Phaeobacter gallaeciensis</it>, <it>Phaeobacter inhibens</it>, <it>Roseobacter denitrificans </it>and <it>Roseobacter litoralis </it>were tested. For this purpose an antibiotic resistance screening was performed and suitable genetic markers were selected. Based on these transformation protocols stably maintained plasmids were identified. A plasmid encoded oxygen-independent fluorescent system was established using the flavin mononucleotide-based fluorescent protein FbFP. Finally, a chromosomal gene knockout strategy was successfully employed for the inactivation of the anaerobic metabolism regulatory gene <it>dnr </it>from <it>D. shibae </it>DFL12^T.</p> <p>Conclusion</p> <p>A genetic toolbox for members of the <it>Roseobacter </it>clade was established. This provides a solid methodical basis for the detailed elucidation of gene regulatory and metabolic networks underlying the ecological success of this group of marine bacteria.</p

A lipocalin mediates unidirectional heme biomineralization in malaria parasites.

During blood-stage development, malaria parasites are challenged with the detoxification of enormous amounts of heme released during the proteolytic catabolism of erythrocytic hemoglobin. They tackle this problem by sequestering heme into bioinert crystals known as hemozoin. The mechanisms underlying this biomineralization process remain enigmatic. Here, we demonstrate that both rodent and human malaria parasite species secrete and internalize a lipocalin-like protein, PV5, to control heme crystallization. Transcriptional deregulation of PV5 in the rodent parasite Plasmodium berghei results in inordinate elongation of hemozoin crystals, while conditional PV5 inactivation in the human malaria agent Plasmodium falciparum causes excessive multidirectional crystal branching. Although hemoglobin processing remains unaffected, PV5-deficient parasites generate less hemozoin. Electron diffraction analysis indicates that despite the distinct changes in crystal morphology, neither the crystalline order nor unit cell of hemozoin are affected by impaired PV5 function. Deregulation of PV5 expression renders P. berghei hypersensitive to the antimalarial drugs artesunate, chloroquine, and atovaquone, resulting in accelerated parasite clearance following drug treatment in vivo. Together, our findings demonstrate the Plasmodium-tailored role of a lipocalin family member in hemozoin formation and underscore the heme biomineralization pathway as an attractive target for therapeutic exploitation

Comparative Single-Cell Analysis of Different E. coli Expression Systems during Microfluidic Cultivation

Binder D, Probst C, Grünberger A, et al. Comparative Single-Cell Analysis of Different E. coli Expression Systems during Microfluidic Cultivation. PLoS one. 2016;11(8): e0160711.Recombinant protein production is mostly realized with large-scale cultivations and monitored at the level of the entire population. Detailed knowledge of cell-to-cell variations with respect to cellular growth and product formation is limited, even though phenotypic heterogeneity may distinctly hamper overall production yields, especially for toxic or difficult-to-express proteins. Unraveling phenotypic heterogeneity is thus a key aspect in understanding and optimizing recombinant protein production in biotechnology and synthetic biology. Here, microfluidic single-cell analysis serves as the method of choice to investigate and unmask population heterogeneities in a dynamic and spatiotemporal fashion. In this study, we report on comparative microfluidic single-cell analyses of commonly used E. coli expression systems to uncover system-inherent specifications in the synthetic M9CA growth medium. To this end, the PT7lac/LacI, the PBAD/AraC and the Pm/XylS system were systematically analyzed in order to gain detailed insights into variations of growth behavior and expression phenotypes and thus to uncover individual strengths and deficiencies at the single-cell level. Specifically, we evaluated the impact of different system-specific inducers, inducer concentrations as well as genetic modifications that affect inducer-uptake and regulation of target gene expression on responsiveness and phenotypic heterogeneity. Interestingly, the most frequently applied expression system based on E. coli strain BL21(DE3) clearly fell behind with respect to expression homogeneity and robustness of growth. Moreover, both the choice of inducer and the presence of inducer uptake systems proved crucial for phenotypic heterogeneity. Conclusively, microfluidic evaluation of different inducible E. coli expression systems and setups identified the modified lacY-deficient PT7lac/LacI as well as the Pm/XylS system with conventional m-toluic acid induction as key players for precise and robust triggering of bacterial gene expression in E. coli in a homogeneous fashion

An apicoplast-resident folate transporter is essential for sporogony of malaria parasites

Malaria parasites are fast replicating unicellular organisms and require substantial amounts of folate for DNA synthesis. Despite the central role of this critical co-factor for parasite survival, only little is known about intraparasitic folate trafficking in Plasmodium. Here, we report on the expression, subcellular localisation and function of the parasite's folate transporter 2 (FT2) during life cycle progression in the murine malaria parasite Plasmodium berghei. Using live fluorescence microscopy of genetically engineered parasites, we demonstrate that FT2 localises to the apicoplast. In invasive P. berghei stages, a fraction of FT2 is also observed at the apical end. Upon genetic disruption of FT2, blood and liver infection, gametocyte production and mosquito colonisation remain unaltered. But in the Anopheles vector, FT2 deficient parasites develop inflated oocysts with unusual pulp formation consisting of numerous single-membrane vesicles, which ultimately fuse to form large cavities. Ultrastructural analysis suggests that this defect reflects aberrant sporoblast formation caused by abnormal vesicular traffic. Complete sporogony in FT2-deficient oocysts is very rare, and mutant sporozoites fail to establish hepatocyte infection, resulting in a complete block of parasite transmission. Our findings reveal a previously unrecognised organellar folate transporter that exerts critical roles for pathogen maturation in the arthropod vector.Deutsche Forschungsgemeinschaft, Grant/ Award Numbers: 419345764, IRTG2290; Francis Crick Institute, Grant/Award Number: FC001043; Wellcome Trust, Grant/Award Number: 210918/Z/18/

Enabling oxygen-controlled microfluidic cultures for spatiotemporal microbial single-cell analysis

Microfluidic cultivation devices that facilitate O2 control enable unique studies of the complex interplay between environmental O2 availability and microbial physiology at the single-cell level. Therefore, microbial single-cell analysis based on time-lapse microscopy is typically used to resolve microbial behavior at the single-cell level with spatiotemporal resolution. Time-lapse imaging then provides large image-data stacks that can be efficiently analyzed by deep learning analysis techniques, providing new insights into microbiology. This knowledge gain justifies the additional and often laborious microfluidic experiments. Obviously, the integration of on-chip O2 measurement and control during the already complex microfluidic cultivation, and the development of image analysis tools, can be a challenging endeavor. A comprehensive experimental approach to allow spatiotemporal single-cell analysis of living microorganisms under controlled O2 availability is presented here. To this end, a gas-permeable polydimethylsiloxane microfluidic cultivation chip and a low-cost 3D-printed mini-incubator were successfully used to control O2 availability inside microfluidic growth chambers during time-lapse microscopy. Dissolved O2 was monitored by imaging the fluorescence lifetime of the O2-sensitive dye RTDP using FLIM microscopy. The acquired image-data stacks from biological experiments containing phase contrast and fluorescence intensity data were analyzed using in-house developed and open-source image-analysis tools. The resulting oxygen concentration could be dynamically controlled between 0% and 100%. The system was experimentally tested by culturing and analyzing an E. coli strain expressing green fluorescent protein as an indirect intracellular oxygen indicator. The presented system allows for innovative microbiological research on microorganisms and microbial ecology with single-cell resolution

Light-responsive control of bacterial gene Expression: precise triggering of the lac promoter activity using photocaged IPTG

Binder D, Grünberger A, Loeschcke A, et al. Light-responsive control of bacterial gene Expression: precise triggering of the lac promoter activity using photocaged IPTG. Integrative biology. 2014;6(8):755-765.Light can be used to control numerous cellular processes including protein function and interaction as well as gene expression in a non-invasive fashion and with unprecedented spatiotemporal resolution. However, for chemical phototriggers tight, gradual, and homogeneous light response has never been attained in living cells. Here, we report on a light-responsive bacterial T7 RNA polymerase expression system based on a photocaged derivative of the inducer molecule isopropyl-β-D-thiogalactopyranoside (IPTG). We have comparatively analyzed different Escherichia coli lac promoter-regulated expression systems in batch and microfluidic single-cell cultivation. The lacY-deficient E. coli strain Tuner(DE3) harboring additional plasmid-born copies of the lacI gene exhibited a sensitive and defined response to increasing IPTG concentrations. Photocaged IPTG served as a synthetic photo-switch to convert the E. coli system into an optogenetic expression module allowing for precise and gradual light-triggering of gene expression as demonstrated at the single cell level. Graphical abstract: Light-responsive control of bacterial gene expression: precise triggering of the lac promoter activity using photocaged IPT

An optogenetic toolbox of LOV-based photosensitizers for light-driven killing of bacteria

Flavin-binding fuorescent proteins (FPs) are genetically encoded in vivo reporters, which are derived from microbial and plant LOV photoreceptors. In this study, we comparatively analyzed ROS formation and light-driven antimicrobial efcacy of eleven LOV-based FPs. In particular, we determined singlet oxygen (1O2) quantum yields and superoxide photosensitization activities via spectroscopic assays and performed cell toxicity experiments in E. coli. Besides miniSOG and SOPP, which have been engineered to generate 1O2, all of the other tested favoproteins were able to produce singlet oxygen and/or hydrogen peroxide but exhibited remarkable diferences in ROS selectivity and yield. Accordingly, most LOV-FPs are potent photosensitizers, which can be used for light-controlled killing of bacteria. Furthermore, the two variants Pp2FbFP and DsFbFP M49I, exhibiting preferential photosensitization of singlet oxygen or singlet oxygen and superoxide, respectively, were shown to be new tools for studying specifc ROS-induced cell signaling processes. The tested LOV-FPs thus further expand the toolbox of optogenetic sensitizers usable for a broad spectrum of microbiological and biomedical applications.Instituto de Investigaciones Fisicoquímicas Teóricas y Aplicada