Protein disulphide isomerase-assisted functionalization of proteinaceous substrates

Protein disulphide isomerase (PDI) is an enzyme that catalyzes thiol-disulphide exchange reactions among a broad spectrum of substrates, including proteins and low-molecular thiols and disulphides. As the first protein-folding catalyst reported, the study of PDI has mainly involved the correct folding of several cysteine-containing proteins. Its application on the functionalization of protein-based materials has not been extensively reported. Herein, we review the applications of PDI on the modification of proteinaceous substrates and discuss its future potential. The mechanism involved in PDI functionalization of fibrous protein substrates is discussed in detail. These approaches allow innovative applications in textile dyeing and finishing, medical textiles, controlled drug delivery systems and hair or skin care products.     

Cytoskeletal elements in cotton seed hair developmentin vitro: Their possible regulatory role in cell wall organization

Summary The localization and orientation of cytoskeletal elements in developing cotton fibres were studied by the indirect immunofluorescence and the dry cleaving technique. Microtubules are transversely arranged to the cell axis, most probably in a flat helix, in the cortex of expanding fibres. Since the innermost deposited cellulose microfibrils always show primarily the same orientation it is postulated that the microtubules control the transverse deposition of the cellulose fibrils. Little further cell expansion takes place during secondary wall formation and the microfibril pattern corresponds to that of the cortical microtubules,e.g., in the steepness of their helicoidal turns. Microtubules with a length of 7–20 m were observed, probably they are longer. The importance of microtubule length on microfibril deposition is discussed. The density of microtubule packing is in the range of 8–14 m^-1 as in other comparable cell types. In contrast to the microtubules, actin filaments are most likely longitudinally oriented during different phases of fibre development. The dry cleaving technique reveals numerous coated pits in the plasma membrane which are not crossed by microtubules. They seem to be linked to the latter by filamentous structures.     

Identification of two novel amyloid A protein subsets coexisting in an individual patient of AA-amyloidosis

Amyloid A protein (AA), the major fibril protein in AA-amyloidosis, is an N-terminal cleavage product of the precursor protein, serum amyloid A (SAA). Using mass spectrometry and amino-acid sequencing, we identified and characterized two novel AA protein subsets co-deposited as amyloid fibrils in an patient having AA-amyloidosis associated with rheumatoid arthritis. One of the AA proteins corresponded to positions 2–76 (or 75) of SAA2α and the other corresponded to positions 2–76 (or 75) of known SAA1 subsets, except for position 52 or 57, where SAA1α has valine and alanine and SAA1β has alanine and valine in position 52 and 57, respectively, whereas the AA protein had alanine at the both positions. Our findings (1), demonstrate that not only one but two SAA subsets could be deposited together as an AA-amyloid in a single individual and (2), support the existence of a novel SAA1 allotype, i.e., SAA1^52,57Ala.     

Histochemical characterization of myotomal muscle in the roach, Rutilus rutilus (L.)

A histochemical study of the myotomal muscles in the roach revealed three main muscle regions: red, intermediate and white. These were distinguished on the basis of glycogen content, succinate dehydrogenase (SDH), and myofibrillar ATPase (mATPase) activity. Except for the red fibre region, none of these described regions is homogeneous. The principal new findings are the toniclike fibre, the presence of a transitional zone with two fibre types, and the mosaic organization of the white fibre region. The significance of this type of myotome architecture in relation to the locomotion of the species is discussed.     

Immunohistochemical characteristics of the constituents of senile plaques and amyloid angiopathy in aged cynomolgus monkeys

Abstract: In this study, we immunohistochemically examined the several constituents of senile plaques (SPs) and cerebral amyloid angiopathy (CAA) in aged cynomolgus monkeys. Apolipoprotein E (apoE) deposited in all mature plaques and CAA, and in half of the diffuse plaques. Alpha-1-antichymotripsin (αACT) deposited in half of the mature plaques and in one third of the CAA. Amyloid precursor protein (APP), ubiquitin (Ub), and microtubule-associated protein-2 (MAP-2) accumulated in the swollen neurites of mature plaques. Glial fibrillary acidic protein (GFAP) was detected in the astrocytes and their processes surrounding the mature plaques. Tau was detected in neither the SPs nor CAA. Therefore, mature plaques involved extracellular Aβ, apoE, and αACT, and also astrocytes and swollen neurites. However, diffuse plaques involved only extracellular Aβ and apoE. Since these features, except for tau, were consistent with those in humans, this animal model will be useful for studying the pathogenesis of cerebral amyloid deposition.     

Rhodamine-phalloidin and anti-tubulin antibody staining of spindle fibres that were irradiated with an ultraviolet microbeam

Summary We irradiated chromosomal spindle fibres in crane-fly spermatocytes with an ultraviolet microbeam of 270 nm wavelength light with total energies near those that cause actin filaments in myofibrils to depolymerize; after irradiation we stained the cells with rhodamine-labelled phalloidin and with anti-tubulin antibodies. In some cells, the irradiation reduced both phalloidin and tubulin staining of the chromosomal spindle fibres; in other cells, the irradiations reduced phalloidin staining but not tubulin staining; in yet other cells, the irradiations reduced tubulin staining but not phalloidin staining. In all irradiated cells in which phalloidin staining was reduced in the irradiated areas phalloidin staining also was reduced poleward from the irradiated areas. These results show that phalloidin staining of chromosomal spindle fibres is not dependent on the presence of kinetochore microtubules, and, therefore, that actin filaments are present in the spindle fibres in vivo. We suggest that actin filaments present in spindle fibres in vivo may be involved in causing chromosome movements during anaphase.     

Systemic amyloidosis in transgenic mice carrying the human mutant transthyretin (Met 30) gene

To analyze the pathologic processes of amyloid deposition in type I familial amyloidotic polyneuropathy (FAP), mice were made transgenic by introducing the human mutant transthyretin (TTR) gene(MT-hMet 30). An inbred strain of mouse, C57 BL/6, was chosen. Transgenic mice were killed using ether anesthesia at 3-mo intervals up to 24 mo after birth. In these transgenic mice, amyloid deposition started in the gastrointestinal tract, cardiovascular system, and kidneys and extended to various other organs and tissues with advancing age. The pattern of amyloid deposition was similar to that observed in human autopsy cases of FAP, except for its absence in the choroid plexus and in the peripheral and autonomic nervous systems. We extracted the amyloid fibrils from kidneys of these mice with a human mutant TTR gene and analyzed them immunochemically and electronmicroscopically. Deposited amyloid was shown to be composed of human mutant TTR and mouse serum amyloid P component. Amyloid fibril from transgenic mice was morphologically and immunohistochemically similar to that of human FAP. The most striking pathologic feature of the transgenic mice was the absence of amyloid deposition in the peripheral and autonomic nervous tissues. Thus, other intrinsic factors may be involved in amyloid deposition in the nervous tissues of human FAP.     

Evaluation of polysulfone hollow fibres and ceramic suction samplers as devices for the in situ extraction of soil solution

An investigation was carried out to assess the potential of using polysulfone hollow fibres for the extraction of soil solution. In comparison to ceramic suction samplers the fibres were shown to contain very low levels of potential contaminants and a low exchange capacity. Carry over between individual samples was negligible permitting the accurate monitoring of temporal changes in solution chemistry. Their flexible and root sized nature makes them ideal for sampling small soil volumes. Some concern however remains about retention of colloidal Fe at the fibre interface. When comparing the soil solution of samples extracted with polysulfone fibres with those extracted by ceramic suction samplers, no significant differences in solute concentrations were observed. No sample contamination resulting from dissolution of Al or Si from the ceramic cup was detected. Analysis of soil solutions collected over a number of extractions, and during and after a rainfall event showed concentrations of elements in solution to remain relatively constant with time.     

Methenamine-Silver Staining: a Simple and Sensitive Staining Method for Senile Plaques and Neurofibrillary Tangles

An improved methenamine-silver impregnation method is presented which exhibits sensitivity for amyloid substances comparable to that of anti-β protein immunostaining. In optimally treated sections, this technique stained both β-amyloid deposits and neurofibrillary tangles, which are known to have a β-pleated structure. This simple procedure allows a large number of sections to be stained for routine examination.