Stability and cytotoxicity of DPPH inhibitory peptides derived from biodegradation of chicken feather

The antioxidant activity and cell viability of feather hydrolysates obtained with the Bacillus licheniformis were evaluated using an in-vitro model. The results indicate that feathers-derived peptides under 3 kDa have antioxidant activity with IC₅₀ values of 5.03 ± 0.215 mg/mL by using DPPH antioxidant assay. Although the antioxidant activity of the peptides under 3 kDa preserved after applying diverse heating (from 20 to 100 °C), they lost their activity under strongly acidic or alkaline conditions. Antioxidant activity of the mixed feather bioactive peptides (MFBPs) obtained with partial purification of peptides under 3 kDa was with IC₅₀ amount of 0.169 mg/mL ± 0.004 using DPPH radical scavenging assay. Also, MFBPs within an amount range of from 0.0048 to 5.0 mg/mL, illustrated no cytotoxicity to gingival fibroblast blood cell lines. In light of our results, the obtained value-added peptides could be useful in different food products as a future functional ingredient with antioxidant potency.

Identification of the Ovine Keratin-Associated Protein 2-1 Gene and Its Sequence Variation in Four Chinese Sheep Breeds

Keratin-associated proteins are important components of wool fibers. The gene encoding the high-sulfur keratin-associated protein 2-1 has been described in humans, but it has not been described in sheep. A basic local alignment search tool nucleotide search of the Ovine Genome Assembly version 4.0 using a human keratin-associated protein 2-1 gene sequence revealed a 399-base pair open reading frame, which was clustered among nine previously identified keratin-associated protein genes on chromosome 11. Polymerase chain reaction-single strand conformation polymorphism analysis revealed four different banding patterns, with these representing four different sequences (A-D) in Chinese sheep breeds. These sequences had the highest similarity to human keratin-associated protein 2-1 gene, suggesting that they represent variants of ovine keratin-associated protein 2-1 gene. Nine single nucleotide variations were detected in the gene, including one non-synonymous nucleotide substitution. Differences in variant frequencies between fine-wool sheep breeds and coarse-wool sheep breeds were detected. The gene was found to be expressed in various tissues, with the highest expression level in skin, and moderate expression levels in heart and lung tissue. These results reveal that the ovine keratin-associated protein 2-1 gene is variable and suggest the gene might affect variation in mean fiber diameter.

Tough and Functional Cross-linked Bioplastics from Sheep Wool Keratin

Novel bioplastic films derived from wool keratins were prepared by protein solution in an alkaline mild oxidative method that splits disulphide (-S-S-) bonds. The native structure of the keratin macromolecules was partially modified upon extraction as revealed by the decrease of the β-sheet to α-helices/coils ratio but high molecular weight fractions (31, 22 and 13 KDa) was retained permitting film formation and plastic behaviour of films. Keratin films were plasticised with glycerol and sodium dodecyl sulphonic acid (SDS), which provided different hydrophobic character to bioplastics. Water content in the films depend on the relative humidity (RH), being able to absorb up to 35 wt% H2O at an ambient of 80% RH. Films were mechanically, thermally and optically analysed. The spectroscopic analyses revelled that these bioplastic films absorb UV light, what is interesting for packaging applications. Thermogravimetric and thermomechanical analysis revealed high stability of keratin macromolecules up to 200 °C with no inherent thermal transitions. Tough bioplastics (19 ± 4 MJ∙ m-3) were obtained after thermal cross-linking with glycerol and formaldehyde outperforming mechanical properties previously reported for protein films.

Chicken feathers as a natural source of sulphur to develop sustainable protein films with enhanced properties

In this work, the effect of hydrolyzed keratin on the properties of soy protein-based films was analyzed when different manufacture processes were employed. It is widely known that the processing method selected can affect the film properties as a function of the structure obtained during the film formation. Therefore, the assessment of hydrolyzed keratin/soy protein films processed by casting and compression moulding was carried out by means of the analysis of physicochemical, thermal, mechanical, optical and surface properties. It was observed that the incorporation of hydrolyzed keratin, obtained from a simpler, environmentally friendlier and more sustainable extraction method, resulted in the improvement of the thermal stability of the films, irrespective of the processing method employed. Moreover, the films processed by compression moulding showed enhanced tensile strength, which increased with the incorporation of hydrolyzed keratin due to the formation of disulfide bonds.

Molecular markers in keratins from Mysticeti whales for species identification of baleen in museum and archaeological collections

Baleen has been harvested by indigenous people for thousands of years, as well as collected by whalers as an additional product of commercial whaling in modern times. Baleen refers to the food-filtering system of Mysticeti whales; a full baleen rack consists of dozens of plates of a tough and flexible keratinous material that terminate in bristles. Due to its properties, baleen was a valuable raw material used in a wide range of artefacts, from implements to clothing. Baleen is not widely used today, however, analyses of this biomolecular tissue have the potential to contribute to conservation efforts, studies of genetic diversity and a better understanding of the exploitation and use of Mysticeti whales in past and recent times. Fortunately, baleen is present in abundance in museum natural history collections. However, it is often difficult or impossible to make a species identification of manufactured or old baleen. Here, we propose a new tool for biomolecular identification of baleen based on its main structural component alpha-keratin (the same protein that makes up hair and fingernails). With the exception of minke whales, alpha-keratin sequences are not yet known for baleen whales. We therefore used peptide mass fingerprinting to determine peptidic profiles in well documented baleen and evaluated the possibility of using this technique to differentiate species in baleen samples that are not adequately identified or are unidentified. We examined baleen from ten different species of whales and determined molecular markers for each species, including species-specific markers. In the case of the Bryde's whales, differences between specimens suggest distinct species or sub-species, consistent with the complex phylogeny of the species. Finally, the methodology was applied to 29 fragments of baleen excavated from archaeological sites in Labrador, Canada (representing 1500 years of whale use by prehistoric people), demonstrating a dominance of bowhead whale (Balaena mysticetus) in the archaeological assemblage and the successful application of the peptide mass fingerprinting technique to identify the species of whale in unidentified and partially degraded samples.

A High-Yield Two-Hour Protocol for Extraction of Human Hair Shaft Proteins

Proteome analysis of the human hair remains challenging due to the poor solubility of hair proteins and the difficulty in their extraction. In the present study, we have developed a rapid extraction protocol for hair shaft protein using alkaline-based buffer. The new protocol accelerated the procedure by reducing the extraction time from at least a day to less than two hours and showed a protein recovery of 47.3 ± 3.72%. Further analyses of the extracted protein sample through sodium dodecyl sulfate polyacrylamide gel electrophoresis and Quadrupole-time-of-flight mass spectrometry analysis unveiled a total of 60 proteins, including 25 that were not previously reported. Identification of these proteins is anticipated to be crucial in helping to understand the molecular basis of hair for potential applications in the future.

Plasmacytoma with Aberrant Expression of Myeloid Markers, T-cell Markers, and Cytokeratin

Plasmacytomas are localized neoplastic proliferations of monoclonal plasma cells. When multifocal, the process is referred to as multiple myeloma. These lesions exhibit a pattern of antigen expression and cytomorphology that usually leads to a ready diagnosis. However, potentially troublesome variations in immunophenotype occur. We describe a case of a plasmacytoma from a patient who presented with sudden onset of pain and a lytic lesion of the left proximal humerus. Hematoxylin and eosin-stained sections showed a lymphoproliferative lesion composed of large lymphoid cells, some with plasmacytoid and immunoblastic features. The lesion also showed significant mitotic activity. Immunohistochemical staining was positive for CD45 (LCA), CD56 (N-CAM), CD43 (MT1), and cytokeratin CAM5.2. There was also clonal staining for λ light chains. In addition, flow cytometric analysis showed positivity for myeloid markers such as CD13, CD33, CD38, and CD138. Significant negative markers include CD20 (L26), CD45RO (UCHL-1), and CD79α. The unusual phenotypic features of this plasmacytoma illustrate potential diagnostic pitfalls. It is important to fully study such lesions to correctly classify them, because this has significant impact on prognosis and management.

The epidermal barrier to Schistosoma mansoni infection

The stratified epithelium serves as protection for underlying tissues and organs, and the structural fitness of the epidermal cells has been extensively reported. We studied the possible roles played by the epidermis as a barrier against the migration of Schistosoma mansoni larvae. Freshly shed cercariae were collected and placed on the back skin of 2-day-old rats. Electron microscopy of biopsies taken at various intervals showed the larvae and their secretory granules in keratinocytes in which the cytoplasm had become homogeneous in appearance. SDS gel electrophoresis showed the digestion of purified epidermal keratin (60K protein) by a proteinase secreted from cercariae, but this activity was inhibited by an inhibitor purified from epidermal cells. These findings suggest that epidermal cells function both structurally and chemically as a barrier against cercariae invasion.

Biopsy of a 5 mm cystic lesion on the right heel of a 48-year-old woman

An excisional biopsy of an asymptomatic cystic lesion that had been present for several years on the right heel of a 48-year-old woman revealed a subcutaneous cyst lined by ciliated columnar epithelium. On immunostaining, the epithelial cells were positive for Pan-cytokeratin (CK AE 1/3), estrogen receptor (ER) and progesterone receptor (PR), but negative for carcinoembryonic antigen (CEA), suggesting Mullerian type of epithelium. Cutaneous ciliated cyst of Mullerian type occurs almost exclusively on the lower extremity of premenopausal women. The lesion is benign and excision is curative.

Preparation and characterization of hair keratin/gelatin blend films

Abstract: Keratin solution was extracted from human hairs and used as subject for preparation of keratin/gelatin blend films. This study was aimed to explore the suitable method using for keratin extraction and extend to study the blend film properties. The blend films were prepared by simple evaporation method. After homogeneously mixed between keratin and gelatin solution at different ratios, the solution were placed on the plates and left in an oven at 40 degrees C for 3 days. All of the films were then analyzed for their morphology, secondary structures and thermal properties by using SEM, FTIR and TGA, respectively. The result from SEM images showed that native keratin films have the highest rough surface compared to other films. In addition, the smooth surface of films gradually increased when the gelatin content increased. Keratin blending with gelatin showed structural changes, especially at the absorption bands of 3300-2900 cm(-1) as well as the amide I, II and III regions. Moreover, thermal properties of the keratin films were enhanced by blending with gelatin. This study suggested that gelatin help to improve some properties of keratin while still remain its strength.

In vivo dedifferentiation of human epidermal cells

Consistent with our previous study, we herein offer further evidence to demonstrate the dedifferentiation of differentiating epidermal cells into stem cells or stem cells -like in vivo. The epidermal sheets eliminated of basal cells were labeled with 6-diamidino-2-phenylindole (DAPI), and then were transplanted onto the full-thickness skin wounds nude mice. Immunohistochemical examination of the survival sheets showed that some cells were positive for both DAPI and either cytokeratins (CK19, CK14) or beta1 integrin in spinous and granular layers at day 7 after transplantation. Furthermore, there was a significant increase in the percentages of both alpha6briCDdim and alpha6briCD71bri populations in survival epidermal sheet grafts 7 d after transplantation compared with those before xenotransplantation (P<0.05), as determined by flow cytometry. The results collectively indicated that some of the differentiated cells in engrafted epidermal sheets dedifferentiated into stem cells or stem cells-like in vivo, which offer us new evidence and insights into the dedifferentiation.

New keratin isolates: actives for natural hair protection

Hair is primarily composed of keratin proteins and it is well established that peptides and proteins bestow desirable effects on the hair, for example improving moisturization and softness. In the present work we describe how keratin actives with unique properties convey a range of beneficial properties to a variety of hair types. It has been observed that these functional keratins protect hair from damage associated with chemical treatments such as perming and relaxation, help to restore the mechanical strength of damaged fibers and decrease fading of colored hair.

Treatment of keratin intermediate filaments with sulfur mustard analogs

Sulfur mustard (SM) is an alkylating agent with a history of use as a chemical weapon. The chemical reactivity of sulfur mustard toward both proteins and nucleic acids coupled with the hours long delay between exposure and appearance of blisters has prevented the determination of the mechanism of blister formation. We have treated assembled keratin intermediate filaments with analogs of sulfur mustard to simulate exposure to SM. We find that treatment of intact filaments with chloroethyl ethyl sulfide (CEES) or mechlorethamine (MEC) produces aggregates of keratin filaments with little native appearing structure. Treatment of a mix of epidermal keratins 1/10 (keratin pair 1 and 10) and keratins 5/14 with a sulfhydryl-specific modification reagent also results in filament abnormalities. Our results are consistent with the hypothesis that modification of keratins by SM would result in keratin filament destruction, leading to lysis of epidermal basal cells and skin blistering.

Establishment and characterization of a spindle cell squamous carcinoma cell line

BACKGROUND

Spindle cell squamous carcinoma (SCSC) is a rare and peculiar biphasic malignant neoplasm that occurs mainly in the upper aerodigestive tract. It consists of sarcomatoid proliferation of pleomorphic spindle-shaped cells and squamous cell carcinoma.

METHODS

Here, we established a SCSC cell line from a tumour arisen in gingiva. We characterized the feature of a SCSC cell line by immunohistochemistry. To know the biological feature, we examined the cell growth, invasiveness and epithelial-mesenchymal transition markers of a SCSC cell line in comparison with oral squamous cell carcinoma (OSCC) cell lines.

RESULTS

By immunohistochemical analyses, the primary tumour expressed cytokeratin and vimentin, indicating carcinosarcoma-like characters. This tumour also showed overexpression of p53 protein. Cultured SCSC cells resulted in bypass of crisis and maintenance over passage 100. The established SCSC cell line was spindle-shaped and showed identical immunohistochemical characters to those of primary tumour cells. Similar to the primary tumour, the cell line showed p53 overexpression and had p53 mutation at codon 132: AAG (lys)-->AAT (asp). The SCSC cell line grew slower than two other OSCC cell lines (MSCC-1 and HSC-2), whereas SCSC cells had remarkable invasiveness in comparison with these cell lines. Moreover, SCSC cells expressed wnt-5a and vimentin mRNA at high levels, but did not express E-cadherin mRNA. This expression pattern of the markers was similar to that of mesenchymal cells, not of epithelial cells.

CONCLUSION

In the present study, we newly established a SCSC cell line with strong invasiveness. This is the first report on the establishment of SCSC cell line. The SCSC cell line can be a useful cell model for the study to know the cytodifferentiation and nature of SCSC.

Unzipping the cuticle of the human hair shaft to obtain micron/nano keratin filaments

An attempt has been made to obtain intact individual keratin filaments of various levels from micron cortical, micron macrofibril to nano intermediate filament and polypeptide alpha-helix from the human hair shaft. The feasibility of this initiative has been largely demonstrated by finding that there is a longitudinal seam/zipper on the cuticle of the human hair shaft, which can be unzipped by certain solvents such as performic acid and urea, allowing one to use an anatomical approach to separate intact individual micron/nano filaments. Micron cortical and macrofibril filaments have been obtained. It is also found that the cortical filaments are twisted together to form a yarn, giving rise to the strength for the hair shaft; and that individual cortical filaments are often 2-2 paired in a similar structure to the double helix.

[Cytokeratin antigen expression in lymph nodes--prognostic significance of clinical features of the primary tumor and lymph nodes in the presence of micrometastases in laryngeal carcinoma]

Lymph node micrometastases in patients with squamous cell carcinoma of the larynx found node-negative by conventional histology may be discovered by immunohistochemistry, particularly by using mono- and policlonal antibodies which are reactive with epithelial cells. Then tumors classified as pN0 by routine methods may be reclassified more correctly as pN1. Authors investigated the incidence of micrometastases in the neck dissection specimens originally staged as pN0 from 22 patients with laryngeal cancer treated surgically at ENT Department Medical University of Lodz between 1998-1999 according to: the survival, using immunostaining with panel of mono- and policlonal antibodies to cytokeratins CK1, CK4, CK5, CK6, CK8, CK10, CK13 and CK18. The relationship between micro-metastases and clinical features of primary tumor and lymph nodes has been discussed.

[Study on the active protein fractions from scorpii tegument]

OBJECTIVE

Extracting the total protein from scorpii tegument, investigating its effect on immune system by transformation of T/B cell.

METHOD

Water-soluble protein(ST1) was extracted by distilled water method and salting-out method, while keratin(ST2) by deoxidization method. Sephadex G-50 was used to isolate the protein. The effects of components isolated by sephadex G-50 on T/B and NK cell were investigated.

RESULT

The protein from scorpii tegument could increase the transformation of T/B cell distinctly in vitro, while no apparent effect on NK cell.

CONCLUSION

Protein from scorpii tegument could modulate the immune system, which may offer a new way for people to find protein drugs.

Free-flow isoelectric focusing of proteins remaining in cell fragments following sonication of thyroid carcinoma cells

The method of preparing protein mixtures for electrophoretic analysis of membrane-associated cell proteins was improved. By sonication, about one-half of the proteins of thyroid cells were released into the supernatant, while the other half preferentially comprising membrane proteins still remained in cell fragments, which could be sedimented by centrifugation. After sonication, even those proteins which remained in cell fragments, could completely be dissolved by free-flow isoelectric focusing media. They migrated through the free-flow electrophoresis chamber without forming precipitates. Because of these improvements, it was possible to show that the two thyroid cancer cell lines ML-1 and ONCO-DG1 express cytokeratin 8 at similar rates, but cytokeratins 7 and 18 differently. In addition, the presence of inorganic pyrophosphatase, tubulin-beta-5, and tubulin-beta-1 chains in human thyroid cells was proved for the first time.

Breast Cancer Pseudometastasis in a Sentinel Lymph Node with Cytokeratin-Positive Debris

We report extensive pseudometastasis detected by immunohistochemical (IHC) staining within a sentinel lymph node. An 83-year-old woman underwent simple mastectomy and sentinel lymph node biopsy (SLNB) for infiltrating ductal carcinoma. Intraoperative frozen section of the SLNB specimen appeared histologically negative for metastasis. IHC staining for cytokeratin in permanent sections, however, showed what was reported as micrometastasis in the subcapsular sinus. Since these cells did not resemble the primary tumor cells morphologically, and had actually been called histiocytes in the frozen section, further IHC staining was done. The subcapsular cells were negative for epithelial membrane antigen (EMA) staining, but they were positive for CD68, a macrophage marker. Thus the cytokeratin-positive cells were not metastatic breast tumor cells, but rather were histiocytes with phagocytized cytokeratin debris. This case report illustrates that IHC staining for cytokeratin in SLNB specimens for breast cancer must be supported by morphologic assessment and further appropriate staining before it can become the basis for treatment decisions.

[Alcoholic and non-alcoholic steatohepatitis]

Morphologic criteria of steatohepatitis are steatosis, ballooning of hepatocytes, often but not constantly associated with Mallory bodies, pericellular fibrosis and inflammation. Liver cirrhosis follows in about 20-50%. With respect to etiology an alcoholic and non-alcoholic type can be distinguished, the latter being a characteristic hepatic lesion associated with the metabolic syndrome (type II diabetes, insulin resistance, obesity, dyslipidemia). Ballooning of hepatocytes as well as Mallory body formation are associated with a disturbance of the keratin intermediate filament cytoskeleton. Mallory bodies are protein aggregates consisting of keratin (particularly keratin 8), p62, a stress-induced adapter protein involved in signal transduction pathways, heat shock proteins, and ubiquitin. Oxidative stress is involved in Mallory body formation. Major sources of oxidative stress in alcoholic and non-alcoholic steatohepatitis are the microsomal biotransformation system (cytochrome P-450) and the mitochondria, together with an impaired antioxidant defense system. Oxidative stress leads to misfolding/unfolding, abnormal phosphorylation of keratins and disturbance of keratin 8: keratin 18 ratio, and thus interferes with intermediate filament assembly. Moreover, impairment of cellular defense against abnormal proteins, i. e. chaperone action and proteasomal degradation, leads to the accumulation of abnormal aggregation--prone keratins (particularly keratin 8) which after ubiquitination associate with the stress-induced ubiquitin-binding protein p62 to form Mallory bodies. Thus, Mallory body formation resembles an "off-folding" protein response of the amyloid type. These pathogenetic principles of the human disease are supported by immunohistochemical and gene expression studies in experimental animals and by transfection experiments in tissue culture cells.

Characterization of beta-keratins and associated proteins in adult and regenerating epidermis of lizards

Reptilian epidermis contains two types of keratin, soft (alpha) and hard (beta). The biosynthesis and molecular weight of beta-keratin during differentiation of lizard epidermis have been studied by autoradiography, immunocytochemistry and immunoblotting. Tritiated proline is mainly incorporated into differentiating and maturing beta-keratin cells with a pattern similar to that observed after immunostaining with a chicken beta-keratin antibody. While the antibody labels a mature form of beta-keratin incorporated in large filaments, the autoradiographic analysis shows that beta-keratin is produced within the first 30 min in ribosomes, and is later packed into large filaments. Also the dermis incorporates high amount of proline for the synthesis of collagen. The skin was separated into epidermis and dermis, which were analyzed separately by protein extraction and electrophoresis. In the epidermal extract proline-labeled proteic bands at 10, 15, 18-20, 42-45, 52-56, 85-90 and 120 kDa appear at 1, 3 and 5 h post-injection. The comparison with the dermal extract shows only the 85-90 and 120 kDa bands, which correspond to collagen. Probably the glycine-rich sequences of collagen present also in beta-keratins are weakly recognized by the beta-1 antibody. Immunoblotting with the beta-keratin antibody identifies proteic bands according to the isolation method. After-saline or urea-thiol extraction bands at 10-15, 18-20, 40, 55 and 62 kDa appear. After extraction and carboxymethylation, weak bands at 10-15, 18-20 and 30-32 kDa are present in some preparations, while in others also bands at 55 and 62 kDa are present. It appears that the lowermost bands at 10-20 kDa are simple beta-keratins, while those at 42-56 kDa are complex or polymeric forms of beta-keratins. The smallest beta-keratins (10-20 kDa) may be early synthesized proteins that are polymerized into larger beta-keratins which are then packed to form larger filaments. Some proline-labeled bands differ from those produced after injection of tritiated histidine. The latter treatment does not show 10-20 kDa labeled proteins, but tends to show bands at 27, 30-33, 40-42 and 50-62 kDa. Histidine-labeled proteins mainly localize in keratohyalin-like granules and dark keratin bundles of clear-oberhautchen layers of lizard epidermis, and their composition is probably different from that of beta-keratin.

Isolation of nucleic acid binding proteins: an approach for isolation of cell surface, nucleic acid binding proteins

An approach for isolation of cell surface, nucleic acid binding proteins is described. This approach relies on affinity modification of the proteins of living cells with reactive oligonucleotides bearing a haptenic group. Covalently modified proteins were isolated by hapten-specific affinity chromatography with subsequent SDS-PAGE. Isolated 68-kDa proteins responsible for the binding of oligonucleotides were MS/MS sequenced and identified as keratin K1, keratin K10, keratin K2e, and albumin.

Postsecretory processing generates multiple cathelicidins for enhanced topical antimicrobial defense

The production of antimicrobial peptides and proteins is essential for defense against infection. Many of the known human antimicrobial peptides are multifunctional, with stimulatory activities such as chemotaxis while simultaneously acting as natural antibiotics. In humans, eccrine appendages express DCD and CAMP, genes encoding proteins processed into the antimicrobial peptides dermcidin and LL-37. In this study we show that after secretion onto the skin surface, the CAMP gene product is processed by a serine protease-dependent mechanism into multiple novel antimicrobial peptides distinct from the cathelicidin LL-37. These peptides show enhanced antimicrobial action, acquiring the ability to kill skin pathogens such as Staphylococcus aureus and Candida albicans. Furthermore, although LL-37 may influence the host inflammatory response by stimulating IL-8 release from keratinocytes, this activity is lost in subsequently processed peptides. Thus, a single gene product encoding an important defense molecule alters structure and function in the topical environment to shift the balance of activity toward direct inhibition of microbial colonization.

Innate immune defense of the nail unit by antimicrobial peptides

BACKGROUND

The nail is susceptible to microbial invasion, yet is usually able to defend itself from infection. This occurs despite isolation from cell-mediated immunity.

OBJECTIVE

The aim of this study was to determine whether soluble innate immune molecules are present in the nail environment that can protect against microbial colonization.

METHODS

Chromatographic techniques were used to purify cationic antimicrobial molecules from porcine hoof extracts. Sections of human and mouse digits were immunostained with antibodies to each species' cathelicidin antimicrobial peptide. Liquid antimicrobial assays were used to determine the activity of these molecules against relevant pathogens.

RESULTS

Human, porcine, and murine nails contain antimicrobial molecules, and the human cathelicidin LL-37 can kill Candida albicans.

CONCLUSION

The presence of antimicrobial peptides in nails with activity against relevant nail pathogens may account for the ability of the nail unit to resist infection in the absence of direct access to the cellular immune system.

Cell surface oligonucleotide-binding proteins of human squamous carcinoma A431 cells

Affinity modified with Flu-DAP-p(N)16degU oligonucleotide-binding proteins were isolated by affinity chromatography using Ultrogel A2-anti fluorescein antibodies. After separation by SDS-PAGE the proteins with molecular masses about 68 kDa were MS/MS sequenced and identified as keratin K1, keratin K10, keratin K2e and albumin.

Identification of cytokeratins in bovine sperm outer dense fibre fractions

Outer dense fibres (ODF) are important substructures of mammalian sperm tails that are involved in the regulation of sperm motility. In this study, we investigated the identity of several sodium dodecyl sulphate (SDS)-insoluble ODF proteins. Bovine ODF were purified by separating sperm heads and tails using ultrasound and Percoll(R) density gradient centrifugation. Sperm flagella were treated with the detergent cetyltrimethylammonium bromide (CTAB). CTAB-insoluble material, which reportedly represents the ODF fraction, was collected, and electron microscopy confirmed a highly purified ODF fraction. We found after solubilization of this fraction with SDS that high amounts of insoluble material were retained after centrifugation. SDS-insoluble material was collected and quantitatively dissolved in 8 M urea. SDS-gel electrophoresis in the presence of urea revealed polypeptides with apparent molecular masses of approximately 25, 43, and 50 kDa. Subsequent immunoblotting with anti-cytokeratin antibodies detected two urea-soluble, SDS-insoluble proteins with apparent molecular masses of 45 and 66 kDa. The 45-kDa protein was identified as cytokeratin 19. An antibody reacting with a palette of cytokeratins (CK 1-18 and CK 20), KL1, was the only antibody that reacted with the 66-kDa polypeptide. We conclude that sperm ODF fractions contain at least one each of type I and type II intermediate filaments. As keratins and intermediate filaments are described as rope-like structures, we suggest that these intermediate filaments play an important structural or tension-bearing role in sperm flagella.

Presence and localization of CCK receptor subtypes in calf pancreas

This study was undertaken to confirm the presence of CCK receptor subtypes in calf pancreas and establish their cellular localization. Using specific antibodies against CCKA and CCKB receptors, somatostatin, glucagon and insulin, we were able to confirm by Western blot the presence of both CCK receptor protein subtypes in the calf pancreas as a 80-85-kDa CCKA receptor and 40-45-kDa CCKB receptor. By immunofluorescence, the CCKB receptor colocalizes with the islets' somatostatin delta cells, confirming what was previously shown in other species, as well as on ductal cells. We could not reproduce in the calf its colocalization with glucagon alpha cells as observed in human and rat. Any specific localization of CCKA receptors with our multiple antibodies failed. Our observation that the CCKB receptor subtype is specifically localized on pancreatic delta cells as well as on ductal cells lets us support the hypothesis that in this species, CCK could be involved in somatostatin metabolism as well as hydrelatic secretion; its effect on enzyme secretion would be indirect.

Presence of protein complex is prerequisite for aragonite crystallization in the nacreous layer

We have isolated a protein complex from the nacreous layer of pearl beads and oyster shells. This complex was mainly composed of pearlin and pearl keratin. Addition of a minute amount of the complex to a calcium-carbonate-saturated solution containing Mg2+ induced aragonite crystallization. The complex was dissociated to individual components in the presence of EDTA and urea. Conversely, the complex was reconstituted from a mixture of components upon incubation with Ca2+ and urea. The mixture of the components was unable to induce aragonite crystallization, but the reconstituted complex recovered this capacity. Thus it is concluded that the complex is the indivisible functional unit required for aragonite crystallization.

A rapid extraction procedure of human hair proteins and identification of phosphorylated species

We developed a rapid and convenient extraction procedure of human hair proteins to examine their biochemical properties in detail. This procedure is based upon the fact that the combination of thiourea and urea in the presence of a reductant can effectively remove proteins from the cortex part of human hair. The extracted fraction mainly consisted of hard alpha-keratins with molecular masses of 40-60 kDa, matrix proteins with 12-18kDa, and minor components with 110-115kDa and 125-135kDa on sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE). The protein phosphorylation in human hair was investigated by immunoblotting with antibodies against phosphoserine, phosphothreonine and phosphotyrosine. We found serine phosphorylation in alpha-keratins and matrix proteins and threonine phosphorylation in alpha-keratins. The extraction was also found to be effective when wool, chicken feathers, rat hair and human nails were used as starting materials.

Simultaneous PAGE, immunoblotting, and immunohistochemical analysis of differentiation associated keratins in lesions of the oral mucosa

The expression of differentiation associated high PM Keratin polypeptides of the oral mucosa lesions were studied by immunohistochemical and immunoblotting techniques applied to adjacent sections of each biopsy specimen. The material studied included specimens of leukoplakia, verrucous carcinoma, squamous cell carcinoma, adenocarcinoma and keratoacanthoma. Little or no expression of 65-67 Kd keratins was evident in squamous cell carcinoma and adenocarcinoma. Hyperkeratotic (both benign and dysplastic) lesions such as verrucous carcinoma, leukoplakia, and keratoacanthoma, showed great variations in the intensity of 65-67 bands and a very irregular immunohistochemical staining pattern. Increased amounts of horny substance was usually accompanied by absence of, or decreased expression of 65-67 Kd keratins, thus indicating a change in the polypeptide composition of the horny layer in pathological conditions of the oral epithelium.

Bacterial fimbriae and their peptides activate human gingival epithelial cells through Toll-like receptor 2

Gingival epithelial cells are a central component of the barrier between oral microflora and internal tissues. Host responses to periodontopathic bacteria and surface components containing fimbriae are thought to be important in the development and progression of periodontal diseases. To elucidate this mechanism, we established immortalized human gingival epithelial cells (HGEC) that were transfected with human papillomavirus. HGEC predominantly expressed Toll-like receptor (TLR) 2, but not TLR4 or CD14. They also induced interleukin-8 (IL-8) production when stimulated with Porphyromonas gingivalis fimbriae and Staphylococcus aureus peptidoglycan, but not Escherichia coli-type synthetic lipid A. Furthermore, an active synthetic peptide composed of residues 69 to 73 (ALTTE) of the fimbrial subunit protein, derived from P. gingivalis and similar to a common component of cell wall peptidoglycans in parasitic bacteria, N-acetylmuramyl-L-alanyl-D-isoglutamine (MDP), significantly induced IL-8 production and NF-kappaB activation in HGEC, and these cytokine-producing activities were augmented by a complex of soluble CD14 and lipopolysaccharide-binding protein (LBP). IL-8 production in HGEC stimulated with these bacterial components was clearly inhibited by mouse monoclonal antibody to human TLR2. These findings suggest that P. gingivalis fimbrial protein and its active peptide are capable of activating HGEC through TLR2.

Quantitative structure/retention relationships in affinity chromatography

Affinity chromatography (AC) followed by quantitative structure/retention relationships (QSRR) analysis provides information on both the analytes and the macromolecules forming the stationary phases. QSRR equations derived for test series of analytes (often drugs) are interpreted in terms of structural requirements of the specific binding sites on macromolecules. Chromatographically demonstrated differences in analyte/macromolecule interactions may be relevant to molecular pharmacology and rational drug design. Multiple regression analysis of appropriately designed sets of affinity-chromatographic data may help increase the speed and efficiency of search as for new drugs and reduce the need for in vivo screening. Specific high-performance affinity-chromatographic separations can be optimized by rational selection of chiral columns, the characteristics of which are provided by QSRR.

A new silver staining apparatus and procedure for matrix-assisted laser desorption/ionization-time of flight analysis of proteins after two-dimensional electrophoresis

We report on a new silver stain especially developed for staining large gels (25 cm x 20 cm) from the Hoefer ISO-DALT system for matrix-assisted laser desorption/ionization-time of flight (MALDI-TOF) analysis of proteins. The staining protocol can be summarized as follows: the gels are sensitised in tetrathionate/potassium acetate solution and washed several times in distilled water. After impregnation with silver nitrate, the silver is reduced in the presence of potassium carbonate, thiosulphate and formaldehyde. The staining procedure is stopped with Tris/acetate after which the gels are rinsed and stored in water before spot picking for MALDI-TOF analysis is performed. This protocol has several advantages over existing ones. The gels are stained in a new apparatus that reduces gel handling to a minimum thus also reducing the contamination with keratins to a minimum. The development times in potassium carbonate are very long (up to 40 min) thus improving batch-to-batch reproducibility. Only the surface of the proteins is stained and the silver can be oxidized, thereafter MALDI-TOF can be performed with protein loads as little as 100 micrograms per gel.

Cloning and sequencing of SOB3, a human gene coding for a sperm protein homologous to an antimicrobial protein and potentially involved in zona pellucida binding

We have previously characterized an 18-19 kDa cationic protein, SOB3, that was detected in the epididymis and localized within the acrosome and on the neck region of human spermatozoa. We suggested that it is involved in secondary sperm binding to the zona pellucida. The present study describes its purification to homogeneity by preparative electrophoresis and non-equilibrium pH gradient electrophoresis. Degenerate primers deduced from microsequencing were used to amplify a specific fragment from human epididymal RNA by reverse transcription-polymerase chain reaction (RT-PCR). This 164 bp fragment was extended by 5' and 3'-RACE to obtain the 548 bp full length cDNA. The open reading frame encodes a 170 amino acid protein. SOB3 is a single copy gene. It is 98% identical to prepro-FALL39 and 100% identical to CAP18, two human genes which were initially identified by screening a human bone marrow (lambda)gt11 library, and which encode an antimicrobial protein. Northern blots of human tissues revealed a 1 kb transcript in corpus and cauda epididymis only, while RT-PCR showed presence of the mRNA in the three epididymal regions and also in round spermatids. The above results suggest that SOB3 has two roles in sperm protection and fertilization, depending on its dual origin and final sperm localization.

Cytokeratins of the matrices of the chestnut (torus carpeus) and periople in horses with acute laminitis

OBJECTIVES

To determine whether there is a change in the expression of cytokeratins in the epidermal cells of the non-weight-bearing parts of the limb in horses with acute laminitis and thus determine whether the morphologic changes that develop in the periople and chestnut (torus carpeus) of horses early in acute laminitis are caused by inhibition of keratinocyte differentiation.

ANIMALS

8 horses with acute laminitis.

PROCEDURE

Tissue specimens were obtained from the chestnuts of all 8 horses and from the stratum externum of the hoof wall of 3 horses. Tissue specimens were obtained within 48 hours of the first clinical signs of laminitis. The cytokeratins were characterized by 1- and 2-dimensional gel electrophoresis, and the tissue distribution of the cytokeratins was studied by immunohistochemical staining.

RESULTS

The biochemical findings indicated that the epidermal cells of tissues from horses affected by laminitis contained the same set of cytokeratins as corresponding tissues from clinically normal horses. Immunohistochemistry on sections from specimens of horses with laminitis versus clinically normal horses indicated a difference in the expression of cytokeratin in the basal cells in the matrix of the stratum externum of the hoof wall and in the matrix of the chestnut of horses with laminitis in which the most severe morphologic changes were observed.

CONCLUSIONS

Inhibition of keratinocyte differentiation, as observed by immunohistochemical changes, in cells in parts of the chestnut and periople may indirectly indicate that the observed epidermal changes in horses with laminitis are primary and are unaffected by weight-bearing.

Immunocytochemical and electrophoretic distribution of cytokeratins in the regenerating epidermis of the lizard Podarcis muralis

Using immunocytochemistry at light- and electron-microscope levels, we studied the distribution of three monoclonal antibodies (AE1, AE2, AE3) specific for mammalian alpha-keratins in regenerating lizard epidermis. We also characterized the keratins expressed during this process by immunoblotting after electrophoretic separation. The AE1 antibody is localized in the basal and suprabasal layers of prescaling and scaling epidermis. During the first stages of scale neogenesis, the AE1 antibody also marks the differentiating oberhautchen and beta-layer, but it disappears from these layers as they mature. This antibody does not stain the prekeratinized and keratinized outermost layers in the hinge region. The AE2 antibody labels the superficial wound epidermis, prekeratinizing and keratinized beta- and alpha-layers, but not basal and suprabasal cells. The AE3 antibody labels all living and keratinized epidermal layers, although AE3 immunoreactivity decreases and disappears as the beta-layer matures. The ultrastructural study shows that the AE2 and AE3, but not the AE1, antibodies specifically label small electron-dense areas within the beta-layer, suggesting retention of alpha-keratins. In the stages of tail regeneration examined, immunoblotting with the three antibodies used for the immunolocalization gives a pattern similar to that of the normal epidermis, except distally, where the process of scale differentiation begins. In this region, in addition to the keratin forms discovered in the normal and in proximal regenerating epidermis, an intense low molecular weight band at 40-41 kDa, positive to all three antibodies, is clearly detectable. Furthermore, in the distal region AE1 and AE3 antibodies, but not the AE2, recognize a weak band at 77-78 kDa not present in the normal and proximal epidermis. The localization and the possible role of the different keratins in the regenerating epidermis is discussed.

Group B streptococci and other gram-positive cocci bind to cytokeratin 8

Group B streptococci (GBS) adhere to surface receptors present on epithelial cells; these receptors include fibronectin and laminin. To identify other possible receptors, plasma membranes from A549 cells, a respiratory tract epithelial cell line, were prepared. These plasma membranes were tested in a protein blot analysis using radiolabeled GBS as a probe. GBS adhered to two species, with molecular masses of 50 kDa (p50) and 57 kDa (p57). We concluded that p50 and p57 correspond to two forms of cytokeratin 8 (CK8) on the basis of the following results: (i) protein blot results demonstrated that p50 and p57 exactly comigrated with two forms of CK8 after separation by sodium dodecyl sulfate-polyacrylamide gel electrophoresis (PAGE); (ii) p50 and p57 exactly comigrated with CK8 after separation by two-dimensional PAGE; (iii) CK8 in solution bound to GBS, as demonstrated by immunoblot analysis of proteins from A549 lysates that bound to GBS in a liquid-phase assay; and (iv) radiolabeled GBS bound to A549 lysate-derived CK8 that had been captured in anti-CK8-coated microtiter wells. CK8 bound to COH1-13, an acapsular mutant of COH1, demonstrating that adherence is not mediated by capsular polysaccharide. Trypsin-treated GBS did not bind to CK8, indicating that adherence is mediated via a protein on the surface of GBS. Soluble CK8 bound to six of six GBS strains tested. Soluble CK8 also bound to Staphylococcus aureus, Lactococcus lactis, Enterococcus faecalis, and Streptococcus pyogenes. We hypothesize that adherence of GBS to cytokeratin may be important for maintenance of colonization at sites of keratinized epithelium, such as the vagina, or for adherence of these bacteria to damaged epithelial cells at other sites.

Micrometastases of bone marrow in localized prostate cancer: correlation with established risk factors

PURPOSE

The presence of cytokeratin 18-positive cells in bone marrow correlates with conventional risk factors in many tumors. We examined whether this was also valid for localized or lymphatically spread prostate cancer.

PATIENTS AND METHODS

Immediately before radical prostatectomy, bone marrow aspirates from both sides of the iliac crest were taken from 287 patients. The presence of cells containing cytokeratin 18 was interpreted as micrometastasis.

RESULTS

In patients with negative lymph nodes (n = 219), conventional risk factors (Gleason score, pathologic stage, ploidy, and preoperative prostate-specific antigen) did not correlate with the preoperative detection of cells containing cytokeratin 18. There was also no correlation with lymph node metastases. Furthermore, there was no interdependency between the preoperatively detected number of cells and the established risk factors.

CONCLUSION

We assume the presence of epithelial cells in bone marrow to be an independent parameter, the clinical importance of which must be substantiated by further studies.

Identification of citrulline residues in the V subdomains of keratin K1 derived from the cornified layer of newborn mouse epidermis

Citrulline residues are detected in keratins and filaggrin in the cornified layers of mammalian epidermis. Such citrulline residues are formed by the enzymatic deimination of arginine residues by peptidylarginine deiminase (EC 3.5.3.15). Major deiminated keratins are thought to be partially degraded/disulfide-cross-linked keratin K1 based on the immunoblotting profiles. In order to obtain more definitive evidence of the deimination of keratin K1 and also to investigate its functional significance, we attempted to identify its preferred acting sites of peptidylarginine deiminase. A partially degraded keratin K1 fraction obtained from the cornified layer of newborn mouse epidermis was subjected to limited proteolytic cleavages, and the resulting deiminated peptides were fractionated by sodium dodecyl sulfate-polyacrylamide gel electrophoresis or reverse-phase high-performance liquid chromatography for N-terminal sequencing and/or amino acid analysis. At least two sites were identified, one in the V1 and the other in the V2 subdomains of keratin K1. An undecapeptide sequence covering the latter shows about 70% homology with an undecapeptide sequence in the V2 subdomain of human K1, a presumptive site of deimination. We speculated that the deimination of arginine residues in these subdomains might modulate their interactions with epidermal proteins other than keratins and filaggrin during the terminal stage of epidermal differentiation.

Corneal epithelial-specific cytokeratin 3 is an autoantigen in Wegener's granulomatosis-associated peripheral ulcerative keratitis

PURPOSE

In a previous investigation it was demonstrated that circulating antibodies to a 66-kDa corneal epithelial antigen (BCEA-A) are associated with peripheral ulcerative keratitis (PUK) in patients with Wegener's granulomatosis (WG). The aim of this study was to identify BCEA-A.

METHODS

The 66-kDa antigen was purified from a bovine corneal epithelial protein extract, using DE52 ion exchange chromatography. Purified protein was used to raise rabbit polyclonal antibodies. These antibodies were used to screen a bovine corneal epithelial cDNA expression library. Positive clones were purified and sequenced. Clones were identified by DNA sequence homology searches of the GenBank DNA database.

RESULTS

A cDNA clone that demonstrated strong binding to both the rabbit polyclonal antibody and patient sera, showed 85% homology to rabbit cytokeratin 3 (K3). K3 is a basic cytokeratin specific to corneal epithelium. No bovine DNA sequence for K3 is available. However, bovine K3 is larger than rabbit K3, with a molecular weight of 66 kDa. Immunofluorescence using both patient sera and the rabbit antibody demonstrated a cytoplasmic binding pattern on human corneal epithelium.

CONCLUSIONS

This evidence suggests that the 66-kDa autoantigen (BCEA-A) associated with PUK in WG is cytokeratin 3, and this may form the basis of a diagnostic/prognostic test.

A novel human type II cytokeratin, K6hf, specifically expressed in the companion layer of the hair follicle

In an attempt to identify new members of the human type II hair keratin family by means of 3'- and 5'-RACE methods and cDNA from anagen hair follicles, we detected a sequence that encoded a hitherto unknown type II cytokeratin. The novel cytokeratin comprises 251 amino acids and exhibits the highest sequence homology with K5. Comparative one- and two-dimensional western blots of keratins from anagen hair bulbs, containing or not containing the outer and inner root sheaths (ORS/IRS), and from footsole epidermis with an antibody against the new cytokeratin, revealed its comigration with K6 and its expression in the ORS/IRS complex. We have therefore named the new cytokeratin K6hf, to distinguish it from the various K6 isoforms and to indicate its expression in the hair follicle. Both in situ hybridization with a K6hf-specific cRNA probe and indirect immunofluorescence with the K6hf antibody showed that K6hf is exclusively expressed in the so-called "companion layer" of the hair follicle, a single layered band of flat and vertically oriented cells between the cuboidal ORS cells and the IRS that stretches from the lowermost bulb region to the isthmus of the follicle. Concomitant K17 and K16 expression studies showed that besides suprabasal ORS cells, these cytokeratins are sequentially expressed subsequent to K6hf in companion cells above the hair bulb. Our study confirms the view of a vertically oriented companion layer differentiation. The clearly delayed K17 and K16 expression relative to that of K6hf in companion cells most probably excludes these keratins as possible type I partners of K6hf and suggests the existence of a still unknown type I partner of its own. Thus, not only morphologically but also biochemically, the companion layer is different from the ORS and can therefore be regarded as an independent histologic compartment of the hair follicle.