Su Ma

University of Natural Resources and Life Sciences Vienna | boku · Institute of Food Technology

Candida biofilm-related infections cause increased morbidity and mortality in patients with a reduced immune response. Traditional antifungal therapies have proven to be insufficient as the biofilm matrix acts as a perfusion barrier. Thus, novel methods are required to improve drug delivery and kill Candida within the biofilm. In this study, chitos...

Polymicrobial biofilms related infections are an important clinical problem with classical antibiotics being not sufficient in therapy. Here, curcumin (Cur) was loaded on positively charged chitosan nanoparticles (CSNP). The antibiofilm activities against mono- and polymicrobial biofilms of Candida albicans and Staphylococcus aureus were evaluated....

Infections related to orthopaedic procedures are considered particularly severe when implantation materials are used, because effective treatments for biofilm removal are lacking. In this study, the relatively new approach for infection control by using an Er:YAG laser was tested. This laser vaporizes all water containing cells in a very effective,...

Polymicrobial biofilm related infections have been a major threat in health care. In this study, the co-immobilization of cellobiose dehydrogenase (CDH) and deoxyribonuclease I (DNase) on positively charged chitosan nanoparticles (CSNPs) resulted in a bi-functional nanoparticle (CSNP-DNase-CDH) targeting both biofilm matrix and microorganisms. The...

To study the direct electron transfer (DET) of the multi-cofactor enzyme cellobiose dehydrogenase (CDH) in regard to its orientation on an electrode surface, a recently published, maleimide-based immobilization method was used in combination with site-directed mutagenesis to establish different orientations on an electrode surface. CDH from Myrioco...

Covalent coupling between a surface‐exposed cysteine residue and maleimide groups was used to immobilize variants of Myriococcum thermophilum cellobiose dehydrogenase (MtCDH) at multiwall carbon nanotube electrodes. By introducing individual cysteine residues at particular places on the surface of the flavodehydrogenase domain of the flavocytochrom...

The Front Cover schematically shows electron‐transfer routes of five different types of redox centers found in multi‐cofactor oxidoreductases towards a cytochrome domain, which is capable of direct electron transfer.More information can be found in the Review by S. Ma and R. Ludwig.

Invited for this month's cover picture is Su Ma and Roland Ludwig from BOKU—University of Natural Resources and Life Sciences, Vienna (Austria). The cover picture schematically shows electron‐transfer routes of five different types of redox centers found in multi‐cofactor oxidoreductases towards a cytochrome domain, which is capable of direct elect...

The direct electron transfer (DET) of enzymes has been utilised to develop biosensors and enzymatic biofuel cells. Whereas some enzymes exhibit DET between their active‐site cofactor and the electrode, other oxidoreductases depend on acquired cytochromes as built‐in redox mediators. Their physiological function is to transfer electrons between the...

Mixed fungal and bacterial biofilm associated infections of implants have been a huge challenge in health care because of the increased resistance to antimicrobials and the critical biological differences between fungi and bacteria. In this study, we evaluated the 2-aminobenzimidazole (2ABI) and curcumin (CUR) alone to inhibit planktonic cell growt...

Bacterial biofilms play a key role during infections, which are associated with an increased morbidity and mortality. The classical antibiotic therapy cannot eradicate biofilm-related infections because biofilm bacteria display high drug resistance due to biofilm matrix. Thus, novel drug delivery to overcome biofilm resistance and eliminate biofilm...

In the upper aerodigestive tract, biofilm deposits by oropharyngeal microbes can cause failure of medical polymer devices like voice prostheses. Previous studies on testing of inhibitive strategies still lack of comparability due to varying study protocols concerning growth media, microbial species and growth conditions. Goal of the study was there...

Background: Biofilm formation on voice prostheses in laryngectomized patients usually limits the lifetime of the device. The purpose of this study was to compare the biofilm resistance of different valve flaps of modern voice prostheses in an in vitro simulation of an oropharyngeal biofilm. Methods: Growth of biofilm deposits on valve flaps (n =...

β-1,3-glucan plays a role in non-albicans Candida species biofilm formation and survival of biofilm Candida to stresses. In this study, we evaluated the antibiofilm activity of β-1,3-glucanase, which can degrade poly-β(1 → 3)-glucose of non-albicans Candida species biofilms, on single and mixed species biofilm of non-albicans Candida species, inclu...

β-1,3-glucan plays a role in Candida biofilm formation and survival of biofilm-forming Candida to stresses. In this study, we evaluated the antibiofilm activity of β-1,3-glucanase, which can degrade poly-β(1→3)-glucose of Candida albicans biofilms. Biofilm was dispersed by 55.96%. β-1,3-glucanase had no effect on Candida planktonic growth as well a...

Silicone is frequently used in clinical and medical fields for medical devices. Mixed biofilms composed of Candida and bacterial species causes frequently failure of medical silicone devices, In this in vitro study, we analyzed mixed biofilm formation of clinically isolated non-albicans Candida species and Staphylococcus epidermidis, including Cand...

Objectives Oral candidiasis is one of the most common human fungal infections. While most cases of the Candida species isolated from the oral cavity are Candida albicans, a large number of candidiasis is attributed to non-albicans Candida species. In this study, we aim to evaluate the in vitro inhibition of supernatants of Lactobacillus gasseri and...

This paper presents a new direct electron transfer based-miniaturized glucose/oxygen enzymatic fuel cell (EFC) whose operating ability has been tested in real saliva samples. The bioanode and biocathode are a graphene working electrode and a graphite counter electrode localized on the same screen printed electrode (SPE) modified with poly(vinyl alc...

Lipidic cubic phase systems (LCPs) are excellent carriers for immobilized enzymes due to their biocompatibility and well-defined nanoporous structure. Lipidic cubic phases act as a convenient matrix to incorporate enzymes and hold them in the vicinity of electrode surfaces in their fully active forms. Corynascus thermophilus cellobiose dehydrogenas...

Fungal-bacterial multispecies biofilms play a major role in failure of medical silicone devices, such as voice prostheses in laryngectomiy. In this study, we determined the effect of Lactobacilli supernatant (cell free) on mixed biofilm formation of fungi and bacteria on silicone in vitro. Lactobacilli supernatant inhibited the adhesion (90 min) of...

Direct and Mediated Electrochemistry of Immobilized Cellobiose Dehydrogenase

Polymicrobial biofilms with fungi and bacteria are the leading cause for the failure of medical devices and related infections. In this study, antibiofilm activities of carboxymethyl chitosan (CM-chitosan) on polymicrobial biofilms of Staphylococcus epidermidis and Candida tropicalis in vitro were evaluated. CM-chitosan was effective as a sole agen...

“Kinetics and Electrocatalytic Properties of Cellobiose Dehydrogenase Covalently Immobilised at Electrode Surfaces”

Stable, site-specific immobilization of redox proteins and enzymes is of interest for the development of biosensors and biofuel cells, where the long-term stability of enzymatic electrodes as well as the possibility of controlling the orientation of the biomolecules at the electrode surface have a great importance. Ideally, it would be desirable to...

Background Cellobiose dehydrogenase (CDH) is an extracellular enzyme produced by lignocellulolytic fungi. cdh gene expression is high in cellulose containing media, but relatively low CDH concentrations are found in the supernatant of fungal cultures due to strong binding to cellulose. Therefore, heterologous expression of CDH in Pichia pastoris wa...

Mixed biofilms with fungi and bacteria are the leading cause for the failure of medical silicone devices, such as voice prostheses in laryngectomy. In this study, we determined the effect of carboxymethyl chitosan (CM-chitosan) on mixed biofilm formation of fungi and bacteria on silicone which is widely used for construction of medical devices. Mix...

We report on the development of an amperometric polymer multilayer-based biosensor for the determination of lactose in the presence of high concentrations of glucose. The sensor platform consists of a two-layer system with the first layer (sensing layer) comprising cellobiose dehydrogenase (CDH) bound by electrostatic interactions in a favourite or...

A simple and robust monitoring system for lactate and glucose detection is presented. The system is based on a suitable integrated screen-printed electrode in thin layer flow cell design (TLFCL) to perform flow injection analysis. The TLFCL is consisted of a two working and one counter electrodes made of carbon and a silver pseudoreference electrod...

This study suggests a new approach for the construction of a stable glucose biosensor based on the covalent immobilisation of cysteine genetically engineered CDH from Myriococcum thermophilum onto modified multi-walled carbon nanotubes (MWCNTs). The carbon nanotubes were modified with maleimide groups by using a method introduced in 2014 by Wright...

Although most cases of candidiasis have been attributed to Candida albicans, non-C. albicans Candida species have been isolated in increasing numbers in patients. In this study, we determined the inhibition of carboxymethyl chitosan (CM-chitosan) on single and mixed species biofilm of non-albicans Candida species, including Candida tropicalis, Cand...

Non-albicans Candida species have been isolated in increasing numbers in patients. Moreover, they are adept at forming biofilms. This study analyzed biofilm formation of clinically isolated non-albicans Candida, including Candida tropicalis, Candida krusei and Candida parapsilosis under the influence of different growth media (RPMI 1640, YPD and BH...

Covalent immobilization of engineered Cellobiose Dehydrogenase from Myriococcum thermophilum

Objectives/hypothesis: Silicone voice prostheses are most frequently used in voice rehabilitation of laryngectomized patients. However, the functional device lifetimes are limited due to formation of mixed biofilms. Existing in vitro models simulating biofilm formation are restricted to only short-term periods. Study design: The goal of this stu...

Background: Lytic polysaccharide monooxygenases (LPMOs) belong to the "auxiliary activities (AA)" enzyme class of the CAZy database. They are known to strongly improve the saccharification process and boost soluble sugar yields from lignocellulosic biomass, which is a key step in the efficient production of sustainable economic biofuels. To date,...

Multistep synthesis and electrochemical characterization of an Os complex-modified redox hydrogel exhibiting a redox potential ≈+30 mV (vs. Ag/AgCl 3 m KCl) is demonstrated. The careful selection of bipyridine-based ligands bearing N,N-dimethylamino moieties and an amino-linker for the covalent attachment to the polymer backbone ensures the formati...

Direct electron transfer of redox enzymes that are close to the electrode surface is usually very slow. It may even prove impossible because of the shielding of the active side and/ or redox-active cofactors of the enzyme by the surrounding insulating protein shell. This problem can be resolved by introducing multi-cofactor enzymes in which the ove...

This study suggests a new approach for the construction of a stable glucose biosensor based on the covalent immobilisation of Cellobiose Dehydrogenase from Myriococcum thermophilum (MtCDH) at carbon-based electrodes. Cellobiose Dehydrogenase is a monomeric protein consisting of two domains containing two active sites: heme and FAD. Carbohydrates su...

Unspecific peroxygenase (UPO) is a highly efficient biocatalyst with a peroxide dependent monooxygenase activity and many biotechnological applications, but the absence of suitable heterologous expression systems has precluded its use in different industrial settings. Recently, the UPO from Agrocybe aegerita was evolved for secretion and activity i...

Aspergillus niger is an effective secretor of glycoside hydrolases that facilitate the saprophytic lifestyle of the fungus by degrading plant cell wall polysaccharides. In the present study, a series of dynamic zymography assays were applied to quantify the secreted glycoside hydrolases of A. niger cultured in media containing different carbon sour...

ι-Carrageenases belong to family 82 of glycoside hydrolases that degrade sulfated galactans in the red algae known as ι-carrageenans. The catalytic mechanism and some substrate-binding residues of family GH82 have been studied but the substrate recognition and binding mechanism of this family have not been fully elucidated. We report here the purif...

NMR spectra of the neo-ι-carratetraose. (A) 1H NMR spectrum of neo-ι-carratetraose. (B) 13C NMR spectrum of neo-ι-carratetraose. (DOC)

Gel-filtration on Bio-gel P6 of the neo-ι-carra-oligosaccharides derived from CgiA_Ce degradation. (DOC)

Relative activities of rCgiA_Ce and mutants of R254 and R314. WT: wild type (DOC)

Multiple sequence alignment of the family GH82 carrageenases. (DOC)

Schematic representation of the different structures of the repeating dimeric units of κ- and ι-carrageenan. (DOC)

List of primers used in this study. (DOC)

Oligonucleotides used to mutagenize the CgiA_Ce. (DOC)

Purpose of work: The purpose of this study is to report a ι-carrageenase which degrades ι-carrageenan yielding neo-ι-carratetraose as the main product in the absence of NaCl. The gene for a new ι-carrageenase, CgiB_Ce, from Cellulophaga sp. QY3 was cloned and sequenced. It comprised an ORF of 1,386 bp encoding for a protein of 461 amino acid resid...