238 research outputs found
Secretion and composition of nectar and the structure of perigonal nectaries in Fritillaria meleagris L. (Liliaceae)
Single Honeybee Silk Protein Mimics Properties of Multi-Protein Silk
Honeybee silk is composed of four fibrous proteins that, unlike other silks, are readily synthesized at full-length and high yield. The four silk genes have been conserved for over 150 million years in all investigated bee, ant and hornet species, implying a distinct functional role for each protein. However, the amino acid composition and molecular architecture of the proteins are similar, suggesting functional redundancy. In this study we compare materials generated from a single honeybee silk protein to materials containing all four recombinant proteins or to natural honeybee silk. We analyse solution conformation by dynamic light scattering and circular dichroism, solid state structure by Fourier Transform Infrared spectroscopy and Raman spectroscopy, and fiber tensile properties by stress-strain analysis. The results demonstrate that fibers artificially generated from a single recombinant silk protein can reproduce the structural and mechanical properties of the natural silk. The importance of the four protein complex found in natural silk may lie in biological silk storage or hierarchical self-assembly. The finding that the functional properties of the mature material can be achieved with a single protein greatly simplifies the route to production for artificial honeybee silk
The histochemistry of thiols and disulphides. IV. Protective fixation by organomercurial-formalin mixtures
Formation of mercaptides as the result of adding organomercuric salts to neutral formalin used for fixation was found to protect protein thiols from autoxidation, provided the tissues were washed in distilled and not tap water. Such bloking, in contrast to that given by HgCl 2 , could be reversed quantitatively by mercaptoethanol made strongly acid to keep it from reducing disulphides. However, some cleavage of disulphides by the mercurials themselves caused slight arbfactual thiol staining in a limited number of sites. Three of the nine compounds tested are sufficiently soluble to penetrate tissues with reasonable speed, stable enough to preclude more than incidental mercurial deposits and currently available commercially. Of them, the diuretic mercurial Mersalyl is at present the protecting, agent of choice since methyl- and ethylmercuric chlorides are too toxic to recommend for routine use.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/42846/1/10735_2005_Article_BF01066541.pd
Alkaloid Quantities in Endophyte-Infected Tall Fescue are Affected by the Plant-Fungus Combination and Environment
Identification and characterization of the microRNA transcriptome of a moth orchid Phalaenopsis aphrodite
The structure of the wool follicle with special reference to the growth and form of the fibre
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