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Spider silk protein refolding is controlled by changing pH

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

Structural conformation of spidroin in solution : A synchrotron radiation circular dichroism study

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

A novel marine silk

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

Increased molecular mobility in humid silk fibers under tensile stress

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-

Breaking the 200 nm limit for routine flow linear dichroism measurements using UV synchrotron radiation

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

Beta-silks : enhancing and controlling aggregation

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

An investigation of enzymatic kinetic resolution of racemic clopidogrel

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

Laccase production by Galerina sp. and its application in dye decolorization

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

Anaerobes in Biotechnology

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

Lab-scale production of biogenic sulphide for metal precipitation in remote areas

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

Smoking-induced risk of future cardiovascular disease is partly mediated by cadmium in tobacco : Malmö Diet and Cancer Cohort Study

Background: Smoking is a strong risk factor for cardiovascular disease (CVD) and causes exposure to cadmium, which is a pro-atherosclerotic metal. Cadmium exposure has also been shown to increase the risk of CVD, even after adjustment for smoking. Our hypothesis was that part of the risk of CVD in smokers may be mediated by cadmium exposure from tobacco smoke. We examined this hypothesis in a medi

Universal conductance fluctuations and phase-coherent transport in a semiconductor Bi2O2Se nanoplate with strong spin-orbit interaction

We report on phase-coherent transport studies of a Bi2O2Se nanoplate and on observation of universal conductance fluctuations and spin-orbit interaction induced reduction in fluctuation amplitude in the nanoplate. Thin-layered Bi2O2Se nanoplates are grown by chemical vapor deposition (CVD) and transport measurements are made on a Hall-bar device fabricated from a CVD-grown nanoplate. The measureme

Laparoscopic versus open distal pancreatectomy (LAPOP) : Study protocol for a single center, nonblinded, randomized controlled trial

Background: Earlier nonrandomized studies have suggested that laparoscopic distal pancreatectomy (LDP) is advantageous compared with open distal pancreatectomy (ODP) regarding hospital stay, blood loss, and recovery. Only one randomized study has been conducted showing reduced time to functional recovery after LDP compared with ODP. Methods: LAPOP is a prospective randomized, nonblinded, parallel-