FG Angewandte und Molekulare Mikrobiologie

18 Items

Recent Submissions
Rocking Aspergillus: morphology-controlled cultivation of Aspergillus niger in a wave-mixed bioreactor for the production of secondary metabolites

Kurt, Tutku ; Marbà-Ardébol, Anna-Maria ; Turan, Zeynep ; Neubauer, Peter ; Junne, Stefan ; Meyer, Vera (2018-08-21)

Background Filamentous fungi including Aspergillus niger are cell factories for the production of organic acids, proteins and bioactive compounds. Traditionally, stirred-tank reactors (STRs) are used to cultivate them under highly reproducible conditions ensuring optimum oxygen uptake and high growth rates. However, agitation via mechanical stirring causes high shear forces, thus affecting fun...

Construction of an improved Aspergillus niger platform for enhanced glucoamylase secretion

Fiedler, Markus R. M. ; Barthel, Lars ; Kubisch, Christin ; Nai, Corrado ; Meyer, Vera (2018-06-16)

Background The lifestyle of filamentous fungi depends on the secretion of hydrolytic enzymes into the surrounding medium, which degrade polymeric substances into monomers that are then taken up to sustain metabolism. This feature has been exploited in biotechnology to establish platform strains with high secretory capacity including Aspergillus niger. The accepted paradigm is that proteins bec...

HisB as novel selection marker for gene targeting approaches in Aspergillus niger

Fiedler, Markus R. M. ; Gensheimer, Tarek ; Kubisch, Christin ; Meyer, Vera (2017-03-08)

Background For Aspergillus niger, a broad set of auxotrophic and dominant resistance markers is available. However, only few offer targeted modification of a gene of interest into or at a genomic locus of choice, which hampers functional genomics studies. We thus aimed to extend the available set by generating a histidine auxotrophic strain with a characterized hisB locus for targeted gene int...

Anti-adenoviral artificial microRNAs Expressed from AAV9 vectors inhibit human adenovirus infection in immunosuppressed Syrian hamsters

Schaar, Katrin ; Geisler, Anja ; Kraus, Milena ; Pinkert, Sandra ; Pryshliak, Markian ; Spencer, Jacqueline F. ; Tollefson, Ann E. ; Ying, Baoling ; Kurreck, Jens ; Wold, William S. ; Klopfleisch, Robert ; Toth, Karoly ; Fechner, Henry (2017-09)

Infections of immunocompromised patients with human adenoviruses (hAd) can develop into life-threatening conditions, whereas drugs with anti-adenoviral efficiency are not clinically approved and have limited efficacy. Small double-stranded RNAs that induce RNAi represent a new class of promising anti-adenoviral therapeutics. However, as yet, their efficiency to treat hAd5 infections has only be...

How a fungus shapes biotechnology: 100 years of Aspergillus niger research

Cairns, Timothy C. ; Nai, Corrado ; Meyer, Vera (2018-05-24)

In 1917, a food chemist named James Currie made a promising discovery: any strain of the filamentous mould Aspergillus niger would produce high concentrations of citric acid when grown in sugar medium. This tricarboxylic acid, which we now know is an intermediate of the Krebs cycle, had previously been extracted from citrus fruits for applications in food and beverage production. Two years afte...

Conditional expression of the small GTPase ArfA impacts secretion, morphology, growth, and actin ring position in Aspergillus niger

Fiedler, Markus R. M. ; Cairns, Timothy C. ; Koch, Oliver ; Kubisch, Christin ; Meyer, Vera (2018-05-08)

In filamentous fungi, growth and protein secretion occurs predominantly at the tip of long, thread like cells termed hyphae. This requires coordinated regulation of multiple processes, including vesicle trafficking, exocytosis, and endocytosis, which are facilitated by a complex cytoskeletal apparatus. In this study, functional analyses of the small GTPase ArfA from Aspergillus niger demonstrat...

The Aspergillus giganteus antifungal protein AFPNN5353activates the cell wall integrity pathway and perturbs calcium homeostasis

Binder, Ulrike ; Bencina, Mojca ; Eigentler, Andrea ; Meyer, Vera ; Marx, Florentine (2011-09-23)

Background The antifungal protein AFPNN5353 is a defensin-like protein of Aspergillus giganteus. It belongs to a group of secretory proteins with low molecular mass, cationic character and a high content of cysteine residues. The protein inhibits the germination and growth of filamentous ascomycetes, including important human and plant pathogens and the model organsims Aspergillus nidulans and...

Transcriptome sequencing and comparative transcriptome analysis of the scleroglucan producer Sclerotium rolfsii

Schmid, Jochen ; Müller-Hagen, Dirk ; Bekel, Thomas ; Funk, Laura ; Stahl, Ulf ; Sieber, Volker ; Meyer, Vera (2010-05-26)

Background The plant pathogenic basidiomycete Sclerotium rolfsii produces the industrially exploited exopolysaccharide scleroglucan, a polymer that consists of (1 → 3)-β-linked glucose with a (1 → 6)-β-glycosyl branch on every third unit. Although the physicochemical properties of scleroglucan are well understood, almost nothing is known about the genetics of scleroglucan biosynthesis. Similar...

The low affinity glucose transporter HxtB is also involved in glucose signalling and metabolism in Aspergillus nidulans

dos Reis, Thaila Fernanda ; Nitsche, Benjamin M. ; de Lima, Pollyne Borborema Almeida ; de Assis, Leandro José ; Mellado, Laura ; Harris, Steven D. ; Meyer, Vera ; dos Santos, Renato A. Corrêa ; Riaño-Pachón, Diego M. ; Ries, Laure Nicolas Annick ; Goldman, Gustavo H. (2017-03-31)

One of the drawbacks during second-generation biofuel production from plant lignocellulosic biomass is the accumulation of glucose, the preferred carbon source of microorganisms, which causes the repression of hydrolytic enzyme secretion by industrially relevant filamentous fungi. Glucose sensing, subsequent transport and cellular signalling pathways have been barely elucidated in these organis...

Uptake, physiological responses and technical application of the aquatic fungus Mucor hiemalis EH5 for the removal of cyanobacterial toxins

Balsano, Evelyn (2017)

Many cyanobacteria produce various harmful secondary metabolites, a.k.a. cyanotoxins, which cause global concerns because of their hazardousness to ecosystems and human health. Due to their diversity in origin and structure, cyanotoxins express different biological activities commonly including the generation of oxidative stress. This work focuses on the three most frequently occurring cyanotox...

From axenic to mixed cultures: technological advances accelerating a paradigm shift in microbiology

Meyer, Vera ; Nai, Corrado (2017)

Since the onset of microbiology in the late 19th century, scientists have been growing microorganisms almost exclusively as pure cultures, resulting in a limited and biased view of the microbial world. Only a paradigm shift in cultivation techniques – from axenic to mixed cultures – can allow a full comprehension of the (chemical) communication of microorganisms, with profound consequences for ...

Southern promises: a snapshot of the microbiology research landscape in South America based on bibliometric data

Nai, Corrado (2017-09)

Scientists have a single currency for productivity and impact: published articles. In an effort to map the global research landscape in microbiology, and to obviate the current lack of bibliometric analysis in the field, FEMS—the Federation of European Microbiological Societies—generated a dataset encompassing an exhaustive, worldwide list of microbiology studies for 2013–14, which further incl...

The induction and function of the transcription factor c-myc in macrophages during pneumococcal pneumonia and legionellosis

Kabus, Christin Sophia (2017)

For infectious diseases, effective defense mechanisms which constitute an efficient innate host response are the keys to eliminate invading pathogens. According to different studies, the pathogenicity of bacteria is due to different virulence factors that contribute to overcome those mechanisms. Against that, the immune system evolved a large repertoire to fight the pathogen. Nevertheless, an o...

Application and de novo design of artificial gene switches for Aspergillus niger

Schütze, Tabea (2017)

Aspergillus niger ist ein filamentöser Pilz, der industriell für die Produktion von organischen Säuren und Proteinen genutzt wird. In den letzten Jahren konnte darüber hinaus die Produktion von homo- und heterologen Sekundärmetaboliten gezeigt werden. Obwohl sich A. niger genetisch verändern lässt, gibt es nur wenig induzierbare Genexpressionssysteme. Außerdem ist die Ko-Expression von mehreren...

Engineering of Aspergillus niger for the production of secondary metabolites

Richter, Lennart ; Wanka, Franziska ; Boecker, Simon ; Storm, Dirk ; Kurt, Tutku ; Vural, Özlem ; Süßmuth, Roderich D. ; Meyer, Vera (2014)

Background: Filamentous fungi can each produce dozens of secondary metabolites which are attractive as therapeutics, drugs, antimicrobials, flavour compounds and other high-value chemicals. Furthermore, they can be used as an expression system for eukaryotic proteins. Application of most fungal secondary metabolites is, however, so far hampered by the lack of suitable fermentation protocols for...

Tet-on, or tet-off, that is the question: advanced conditional gene expression in Aspergillus

Wanka, Franziska ; Cairns, Timothy ; Boecker, Simon ; Berens, Christian ; Happel, Anna ; Zheng, Xiaomei ; Sun, Jibin ; Krappmann, Sven ; Meyer, Vera (2016)

In Aspergillus, controlled gene expression is often achieved using the reverse tetracycline-controlled transactivator (rtTA) dependent Tet-on system, whereby transcription is activated in a titratable manner by addition of the tetracycline derivative doxycycline. The complementary Tet-off system utilises the tetracycline-controlled transactivator (tTA) component to quantitatively reduce gene ex...

Gen- und verfahrenstechnische Ansätze zur Optimierung von Aspergillus niger als Expressionsplattform

Wanka, Franziska (2016)

Aspergillus niger has the ability to synthesise large amounts of acids and proteins, and to secrete these into the environment. This particular property is used in biotechnology to produce platform chemicals and industrial enzymes. Despite impressive metabolic activities, there is still a need for research to optimise product yields of A. niger using genetic and engineering approaches. This wo...

The capacity of Aspergillus niger to sense and respond to cell wall stress requires at least three transcription factors: RlmA, MsnA and CrzA

Fiedler, Markus R. M. ; Lorenz, Annett ; Nitsche, Benjamin M. ; Hondel, Cees A. M. J. J. van den ; Ram, Arthur F. J. ; Meyer, Vera (2014-12-01)

Background: Cell wall integrity, vesicle transport and protein secretion are key factors contributing to the vitality and productivity of filamentous fungal cell factories such as Aspergillus niger. In order to pioneer rational strain improvement programs, fundamental knowledge on the genetic basis of these processes is required. The aim of the present study was thus to unravel survival strateg...