Comparison of diazo-coupling, formazan, and silver staining techniques for visualizing alkaline phosphatase isoenzymes after electrophoresis in homogeneous-pore and gradient-pore polyacrylamide gels

Osteogenic potency of dedifferentiated fat cells isolated from elderly people with osteoporosis

Mature adipocytes are the major cell type in adipose tissue. This study aimed to explore the osteogenic potency of dedifferentiated fat cells obtained from osteoporotic patients (opDFATs) in vitro and in vivo. Mature adipocytes and adipose-derived stem cells (opASCs) were harvested from subcutaneous adipose tissue. Mature adipocytes were dedifferentiated to produce opDFATs by the ceiling culture method. OpDFATs were osteogenically induced in vitro with opASCs as a control. Cell growth, alkaline phosphatase (ALPase) activity and cell mineralization were determined, and expression levels of osteogenesis-specific genes (collagen I, osteocalcin and bone sialoprotein) were analyzed using quantitative reverse transcription polymerase chain reaction. After 14 days, the opDFATs were combined with a poly(lactide-co-glycolide)-β-tricalcium phosphate porous scaffold after being suspended in collagen I gel and implanted into nude mice for 4 weeks prior to histological analysis. Unilocular lipid droplets in mature adipocytes gradually split into smaller droplets and disappeared from the cytoplasm. Mature adipocytes dedifferentiated to opDFATs and cell morphology changed from spherical to elongated. High levels of ALPase and cell mineralization were observed in opDFATs by staining. No significant differences were found between the growth curves, ALPase activity, cell mineralization and expression levels of osteogenesis-specific genes between opDFATS and opASCs. After implantation for 4 weeks, new bone tissue was observed histologically in the opDFATs-based biocomposite. OpDFATs are implicated as a novel type of seed cell for bone tissue engineering based on their osteogenic potency and higher abundance in adipose tissue compared with opASCs.

Characterization of thermostable native alkaline phosphatase from an aerobic hyperthermophilic archaeon, Aeropyrum pernix K1

This paper reports the characterization of an alkaline phosphatase (AP) from an aerobic hyperthermophilic Archaeon Aeropyrum pernix K1. The native AP was purified into homogeneity. The enzyme is predicted as a homodimeric structure with a native molecular mass of about 75 kDa and monomer of about 40 kDa. Apparent optimum pH and temperature were estimated at 10.0 and above 95 degrees C, respectively. Magnesium ion increased both the stability and the activity of the enzyme. A. pernix AP has been demonstrated as a very thermostable AP, retaining about 76% of its activity after being incubated at 90 degrees C for 5.5 h and 67% of its activity after being incubated at 100 degrees C for 2.5 h, respectively, under the presence of Mg(II). Enzyme activity was increased in addition of exogenous Mg(II), Ca(II), Zn(II), and Co(II).

Lectin binding in skeletal muscle. Evaluation of alkaline phosphatase conjugated avidin staining procedures

Cryostat sections from rat gracilis muscles were incubated with different biotinylated lectins: Con A (Concanavilin A), WGA (Wheat germ agglutinin), SBA (soybean agglutinin), GS I and GS II (Griffonia simplicifolia agglutinin), LCA (Lens culinaris agglutinin), PNA (peanut agglutinin) and PSA (Pisum sativum agglutinin). The sections were subsequently treated with alkaline phosphatase conjugated avidin. The lectin binding sites were visualized after incubation in substrate media containing: (1) 5-bromo-4-chloro indoxyl phosphate and Nitro Blue tetrazolium or copper sulphate; (2) naphthol AS-MX phosphate or naphthol AS-BI phosphate and various types of diazonium salts; (3) alpha-naphthylphosphate and Fast Blue BB; (4) beta-glycerophosphate according to the method of Gomori. The results obtained with the alkaline phosphatase methods were compared with those seen with a streptavidin-horseradish peroxidase procedure. Several chromogen protocols for visualizing alkaline phosphatase activity showed differences in the ability to detect lectin binding sites. A sarcoplasmic reaction was evident for Con A, GS II, WGA, LCA, and PSA after incubation in the indoxyl phosphate medium. Sarcoplasmic reaction for GS II was also noticed after incubation with naphthol AS-MX Fast Blue BB and beta-glycerophosphate. The latter substrate also gave rise to a sarcoplasmic Con A reaction. With the indoxylphosphate tetrazolium salt method some muscle fibres showed a very strong intracellular reaction after incubation with Con A and GS II while the staining intensity was weak in other fibres. The same muscle fibres were stained with PAS. No sarcoplasmic reactions were observed with either naphthol phosphate media or with the diaminobenzidine peroxidase methods. Further, the staining of the muscle fibre periphery, connective tissue, an capillaries was intensified using the indoxyl method. The indoxylphosphate-tetrazolium salt method seems to be suitable for future investigations of lectin binding sites in muscle sections.