Keratin is a complex and structurally stable protein found in human and animal hard tissues, such as feathers, wool, hair, hoof and nails. Some of these, like feathers and wool, represent one of the ...main sources of protein-rich waste with significant potential to be transformed into value-added products such as feed, fertilizers or bioenergy. A major limitation impeding valorization of keratinous substrates is their recalcitrant structure and resistance to hydrolysis by common proteases. However, specialized keratinolytic enzymes produced by some microorganisms can efficiently degrade these substrates. Keratinases have already found a purpose in pharmaceutical, textile and leather industries. However, their wider implementation in other processes, such as cost-effective (pre)treatment of poultry waste, still requires optimization of production and performance of the available enzymes. Here we present a comprehensive review covering molecular properties and characteristics of keratinases, their classification, traditional and novel approaches in discovery of novel enzymes, production, characterization, improvement and biotechnological applications.
Ruminococcus flavefaciens is among the most important cellulolytic bacterial species in rumen and gastrointestinal tract of monogastric herbivorous animals. Its efficiency in degradation of ...(hemi)cellulosic substrates is associated with the production of remarkably intricate extracellular multienzyme complexes, named cellulosomes. In the present work we investigated the cellulolytic system of 007C. The bioinformatic analysis of the draft genome sequence revealed identical organization of sca gene cluster as has previously been found in four other strains of R. flavefaciens. The cluster consists of five genes in the following order: scaC-scaA-scaB-cttA-scaE. The cellulases of R. flavefaciens 007C belong to four families of glycoside hydrolases, namely GH48, GH44, GH9 in GH5. Majority of these enzymes are putative endoglucanases, belonging to families GH5 and GH9, whereas only one gene encoding GH44 and GH48 was found. Apart from catalytic domains, most of these proteins also contain dockerins – signature sequences, which indicate their attachement to cellulosomes. On the other hand, carbohydrate-binding modules were only found coupled to GH9 catalytic domains. Zymogram analysis showed that larger endoglucanases were mostly constitutively expressed, wheras smaller enzymes were only detected in later phases of Avicel-grown cultures.
Global energy demands and global warming represent key challenges of the future of human society. Continous renewable energy supply is key for sustainable economy development. Waste plant biomass ...represent abundant source of renewable energy that can be transformed to biofuels and other value-added products, which is currently limited due to the lack of cost-effective biocatalysts. The bottleneck of this process is the degradation of structural polysaccharides of plant cell walls to soluble compounds that can be fermented to solvents or transformed to biogas via methanogenesis and can be used as biofuels or chemical raw materials. In order to replace traditional physical and chemical methods of lignocellulose pretreatment with more environmentally friendly biological approaches, native microbial enzyme systems are increasingly being explored as potential biocatalysts that could be used in these processes. Microbial enzymes are useful either as catalysts in the enzymatic hydrolysis of lignocelluloses or as components incorporated in engineered microbes for consolidated bioprocessing of lignocelluloses. The unprecedented development of tools for genetic and metabolic engineering for a wide range of microorganisms enabled significant progress in the development of microbial cell factories optimized for the producton of biofuels. One of the most promising strategies aimed towards this goal, i.e. systematic design and heterologous expression of »designer cellulosomes« in industrial solventogenic strains is adressed in detail.
In the current study, the toxicity mechanism of nanosized CuO (nCuO) to the freshwater ciliated protozoa Tetrahymena thermophila was studied. Changes in fatty acid profile, lipid peroxidation ...metabolites and reactive oxygen species (ROS) were measured. Bulk CuO and CuSO4 served as controls for size and solubility and 3,5-dichorophenol (3,5-DCP) as a control for a chemical known to directly affect the membrane composition. Exposure to all copper compounds induced the generation of ROS, whereas nCuO was most potent. The latter effect was not solely explained by solubilized Cu-ions and was apparently particle-related. 24 h exposure of protozoa to 80 mg/L of nCuO (EC50) significantly decreased the proportion of two major unsaturated fatty acids (UFA) (C18:3 cis-6,9,12, C18:2 cis-9,12), while it increased the relative amount of two saturated fatty acids (SFA) (C18:0, C16:0). Analogous effect was not observed when protozoa were exposed to equitoxic suspensions of bulk CuO, Cu-ions or 3,5-DCP. As changes in the UFA:SFA upon exposure of protozoa to nCuO were not detected at 2 h exposure and no simultaneous dose- or time-dependent lipid peroxidation occurred, it is likely that one of the adaptation mechanisms of protozoa to nCuO was lowering membrane fluidity by the inhibition of de novo synthesis of fatty acid desaturases. This is the first study of the effects of nanoparticles on the membrane fatty acid composition.
Microbial biosensors are analytical devices capable of sensing substances in the environment due to the specific biological reaction of the microorganism or its parts. Construction of a microbial ...biosensor requires knowledge of microbial response to the specific analyte. Linking this response with the quantitative data, using a transducer, is the crucial step in the construction of a biosensor. Regarding the transducer type, biosensors are divided into electrochemical, optical biosensors and microbial fuel cells. The use of the proper configuration depends on the selection of the biosensing element. With the use of transgenic E. coli strains, bioluminescence or fluorescence based biosensors were developed. Microbial fuel cells enable the use of the heterogeneous microbial populations, isolated from wastewater. Different microorganisms are used for different pollutants – pesticides, heavy metals, phenolic compounds, organic waste, etc. Biosensing enables measurement of their concentration and their toxic or genotoxic effects on the microbes. Increasing environmental awareness has contributed to the increase of interest for biomonitoring. Although technologies, such as bioinformatics and genetic engineering, allow us to design complex and efficient microbial biosensors for environmental pollutants, the transfer of the laboratory work to the field still remains a problem to solve.
The bovine rumen maintains a diverse microbial community that serves to break down indigestible plant substrates. However, those bacteria specifically adapted to degrade cellulose, the major ...structural component of plant biomass, represent a fraction of the rumen microbiome. Previously, we proposed scaC as a candidate for phylotyping Ruminococcus flavefaciens, one of three major cellulolytic bacterial species isolated from the rumen. In the present report we examine the dynamics and diversity of scaC-types both within and between cattle temporally, following a dietary switch from corn-silage to grass-legume hay. These results were placed in the context of the overall bacterial population dynamics measured using the 16S rRNA.
As many as 117 scaC-types were estimated, although just nineteen were detected in each of three rumens tested, and these collectively accounted for the majority of all types present. Variation in scaC populations was observed between cattle, between planktonic and fiber-associated fractions and temporally over the six-week survey, and appeared related to scaC phylogeny. However, by the sixth week no significant separation of scaC populations was seen between animals, suggesting enrichment of a constrained set of scaC-types. Comparing the amino-acid translation of each scaC-type revealed sequence variation within part of the predicted dockerin module but strong conservation in the N-terminus, where the cohesin module is located.
The R. flavefaciens species comprises a multiplicity of scaC-types in-vivo. Enrichment of particular scaC-types temporally, following a dietary switch, and between fractions along with the phylogenetic congruence suggests that functional differences exist between types. Observed differences in dockerin modules suggest at least part of the functional heterogeneity may be conferred by scaC. The polymorphic nature of scaC enables the relative distribution of R. flavefaciens strains to be examined and represents a gene-centric approach to investigating the intraspecific adaptation of an important specialist population.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
The manipulation of the human microbiome presents a transformative frontier in addressing prevalent dermatological conditions, like acne and atopic dermatitis. Strategies for skin and gut microbiome ...modification, such as microbiome transplantation and oral or topical application of probiotics, prebiotics, and postbiotics, offer promising solutions for different skin disorders. Bacteriophages, viruses that target bacteria, also provide an alternative microbiome manipulation platform. However, despite the promising initial results, further investigation is essential to unravel the underlying mechanisms, assess efficacy, and ensure safety across diverse populations, as the interplay between microbial communities and skin health is very complex. In the transformative era of microbiome manipulation techniques, it is important to ensure that these are applied beyond the realms of scientific exploration and benefit the global advancement of skin health. This review aims to capture the increasing volume of research in this field that reflects a growing interest and dedication to advancing our understanding of microbiome manipulation techniques with potential applications in dermatology. It represents an overview of the possibilities of treating skin diseases via microbiome modulation, focusing on two of the most common inflammatory skin diseases of today: acne and atopic dermatitis.
Manipulacija človeškega mikrobioma predstavlja izjemen potencial za zdravljenje pogostih dermatoloških stanj, kot so akne in atopijski dermatitis. Strategije manipuliranja kožnega in črevesnega mikrobioma vključujejo transplantacijo mikrobioma, peroralno ali topično uporabo probiotikov, prebiotikov in postbiotikov ter manipulacijo kožnega ali prebavnega mikrobioma z uporabo bakteriofagov. Začetne raziskave, v katerih so omenjene strategije uporabili za zdravljenje nekaterih pogostejših kožnih bolezni so pokazale obetavne rezultate. Naraščajoč obseg raziskav na tem področju pa odraža željo po napredku razumevanja in uporabe tehnik manipulacije mikrobioma v dermatologiji. Ker so interakcije med mikrobioto in kožo zelo kompleksne, je za čim uspešnejši prenos novih znanj v prakso nujno dobro poznavanje tako osnovnih mehanizmov v ozadju teh interakcij, kot ocene učinkovitosti zdravljenja ter zagotavljanje varnosti tovrstnih posegov pri različnih populacijah. Ključno je, da najnovejše informacije in odkritja s tega področja preidejo okvirje znanstvenega raziskovanja in s prenosom spoznanj v prakso lahko pripomorejo h globalnemu izboljšanju zdravja kože. V objavi povzemamo najnovejše raziskave na področju povezav med človeškim mikrobiomom in kože, s poudarkom na potencialih novih pristopih zdravljenja atopijskega dermatitisa in aken z manipulacijo mikrobioma kože in prebavil.
Summary
Type IV pili (T4P) are bacterial surface‐exposed appendages that have been extensively studied in Gram‐negative pathogenic bacteria. Despite recent sequencing efforts, little is known ...regarding these structures in non‐pathogenic anaerobic Gram‐positive species, particularly commensals of the mammalian gut. Early studies revealed that T4P in two ruminal Gram‐positive species are associated with growth on cellulose, suggesting possible associations of T4P with substrate utilization patterns. In the present study, genome sequences of 118 taxonomically diverse, mainly Gram‐positive, bacterial strains isolated from anaerobic (gastrointestinal) environments, have been analysed. The genes likely to be associated with T4P biogenesis were analysed and grouped according to T4P genetic organization. In parallel, consortia of Carbohydrate Active enZYmes (CAZymes) were also analysed and used to predict carbohydrate utilization abilities of selected strains. The predictive power of this approach was additionally confirmed by experimental assessment of substrate‐related growth patterns of selected strains. Our analysis revealed that T4P systems with diverse genetic organization are widespread among Gram‐positive anaerobic non‐pathogenic bacteria isolated from different environments, belonging to two phylogenetically distantly related phyla: Firmicutes and Actinobacteria.
Agriculture is a source of emissions of the greenhouse gas methane into the environment. These emissions can be reduced by appropriate storage of animal slurry and manure, with proper fertilization ...and processing of organic agricultural waste into biogas, where methane is captured and used as an energy source. Biogas is a renewable source of energy that is produced by microbial anaerobic digestion in biogas plants. As a substrate in biogas plants using different types of organic biomass such as animal manure and slurry, crop residues, spoilt silage, waste from food processing industry and biodegradable industrial and municipal waste. Biogas can be used to produce heat and electricity or purified to biomethane as a fuel for vehicles. Digestate can be used as a high-quality fertilizer. Biogas as a renewable energy source represents a replacement for fossil fuels, thus reducing greenhouse gas emissions from fossil sources. The system of financial supports for electricity produced from biogas is applied in Slovenia. There were 24 operating biogas plants in Slovenia in year 2014. Slovenian biogas plants currently produce the majority of biogas from energy crops. As only the minority of biogas is produced from animal excrements we will primarily support the development of agricultural microbiogas plants that will use animal excrements and organic waste biomass from agri-food sector as substrates.
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