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A method evaluating the sensitivity of a given parameter to topological changes is proposed within the method of moments paradigm. The basis functions are used as degrees of freedom which, when compared to the classical pixeling technique, provide important advantages, one of them being impedance matrix inversion free evaluation of the sensitivity. The devised procedure utilizes port modes and the
Propionibacterium acidipropionici produces propionic acid from different sugars and glycerol; the production can be improved by high cell density fermentations using immobilized cells that help to overcome the limitations of the non-productive lag phase and product inhibition. In this study, the use of stress factors to induce P. acidipropionici to form biofilm and its use as an immobilization pro
A two-stage polyethylene glycol (PEG)-phosphate aqueous two-phase system was used for purification of a highly thermostable and alkaline active recombinant xylanase. Response surface methodology (RSM) and artificial neural network (ANN) have been used to develop predictive models for simulation and optimization of purification process. Effects of pH, PEG molecular weight, concentrations of phospha
Amber is known for its remarkably well-preserved fossils, but the chemical complexity of amber and its history are less well known. Amber is highly variable in both its physical and chemical properties, which are dependent on factors such as the source tree and the diagenetic history. Amber from a given locality therefore has a unique chemical composition. Fourier transform infrared (FTIR) spectro
Silks spun by spiders and insects are independently evolved proteinaceous biomaterials with fascinating physical properties attracting scientists from a wide range of disciplines using a wide range of analytical tools. Here we demonstrate the suitability of neutron small angle scattering (SANS) to investigate the morphology and structure of native silk fibroin at near in vivo conditions. Comparing
Spider silks combine basic amino acids into strong and versatile fibers where the quality of the elastomer is attributed to the interaction of highly adapted protein motifs with a complex spinning process. The evaluation, however, of the interaction has remained elusive. Here, we present a novel analysis to study silk formation by examining the secondary structures of silk proteins in solution. Us
Spider silk is spun in a complex and unique process, thought to depend on a hydrophobic conversion of a predominantly disordered to a β-sheet rich protein structures. To test this hypothesis we monitored the effect of cationic (DOTAC) and anionic (alkyl sulfate) detergents and of (ii) solvent polarity using a series of alcohols on the secondary structure transition in dilute solutions of native sp
Orb weaver spiders use exceptionally complex spinning processes to transform soluble silk proteins into solid fibers with specific functions and mechanical properties. In this study, to understand the nature of this transformation we investigated the structural changes of the soluble silk proteins from the major ampullate gland (web radial threads and spider safety line); flagelliform gland (web s
Unlike man-made fibers, the silks of spiders are spun from aqueous solutions and at atmospheric pressure in a process still poorly understood. The molecular mechanism of this process involves the conversion of a highly concentrated, predominantly disordered silk protein (spidroin) into β-sheet-rich structures. To help store and transport the spidroins in solution, as well as probably control their
Spidroins, the major silk proteins making up the spider's dragline silk, originate in two distinct tissue layers (A and B) in the spider's major ampullate gland. Formation of the complex thread from spidroins occurs in the lumen of the duct connected to the gland. Using pH-sensitive microelectrode probes, we showed that the spidroins traveling through the gland and duct experience a monotonic decr
Spider silk is made and spun in a complex process that tightly controls the conversion from soluble protein to insoluble fiber. The mechanical properties of the silk fiber are modulated to suit the needs of the spider by various factors in the animal's spinning process. In the major ampullate (MA) gland, the silk proteins are secreted and stored in the lumen of the ampulla. A particular structural
The discovery of a novel silk production system in a marine amphipod provides insights into the wider potential of natural silks. The tube-building corophioid amphipod Crassicorophium bonellii produces from its legs fibrous, adhesive underwater threads that combine barnacle cement biology with aspects of spider silk thread extrusion spinning. We characterised the filamentous silk as a mixture of m
Silk fibers are semicrystalline nanocomposite protein fibers with an extraordinary mechanical toughness that changes with humidity. Diffusive or overdamped motion on a molecular level is absent in dry silkworm silk, but present in humid silk at ambient temperature. This microscopic diffusion distinctly depends on the externally applied macroscopic tensile force. Quasielastic and inelastic neutron-
The first synchrotron radiation flow linear dichroism spectra are reported. High-quality spectral data can be collected from 450 nm down to 180 nm in contrast to the practical cutoff of approximately 200 nm on benchtop instruments. State-of-the-art microvolume capillary Couette flow linear dichroism was successfully ported to a synchrotron radiation source. The sample volume required is < 50 micro
It appears that fiber-forming proteins are not an exclusive group but that, with appropriate conditions, many proteins can potentially aggregate and form fibrils; though only certain proteins, for example, amyloids and silks, do so under normal physiological conditions. Even so, this suggests a ubiquitous aggregation mechanism in which the protein environment is at least as important as the sequen
This paper presents a biocatalysis based approach for asymmetric hydrolysis of Clopidogrel, one of the most effective antiplatelet aggregators. Instead of the conventional "wet lab" screening method, we used an advanced chemical information retrieval tool, Scifinder®, to find suitable enzyme candidate(s) for the asymmetric hydrolysis. Scifinder® search for reactions similar to the target reaction
The laccase producing fungus HC1 was isolated from a sample collected in the Bolivian Amazon region. Analysis of 5.8S and 28S rDNA, and internal transcribed spacer 1 and 2 sequences revealed that isolate HC1 belongs to genus Galerina. High production of laccase was achieved in basal salt medium supplemented with 30 g L-1 glucose, 10 g L-1 yeast extract and 0.01 g L-1 copper sulphate. The enzyme pr
This book review series presents current trends in modern biotechnology. The aim is to cover all aspects of this interdisciplinary technology where knowledge, methods and expertise are required from chemistry, biochemistry, microbiology, genetics, chemical engineering and computer science.Volumes are organized topically and provide a comprehensive discussion of developments in the respective field
Batch cultures with wheat straw, biomass of Paja Brava (Festuca orthophylla), filter paper, newspaper and beech leaves (Fagus sylvatica) were established to produce sulphide. Sulphide production, sulphate reduction, concentration of Volatile Fatty Acids (VFAs), enzyme activities and Fluorescence in situ hybridisation were determined. Approximately 5 mM of sulphide was produced during anaerobic dig
