Dual fluorescent in situ hybridization and immunohistochemical detection with tyramide signal amplification.

To understand the biological relationships among various molecules, it is necessary to define the cellular expression patterns of multiple genes and gene products. Relatively simple methods for performing multi-label immunohistochemical detection are available. However, there is a paucity of techniques for dual immunohistochemical (IHC) and mRNA in situ hybridization (ISH) detection. The recent development of improved non-radioactive detection systems and simplified ISH protocols has prompted us to develop a tyramide signal amplification method for sequential multi-label fluorescent ISH and IHC detection in either frozen or paraffin-embedded tissue sections. We used this method to examine the relationship between glial cell line-derived neurotrophic factor receptor alpha2 (GFRalpha2) mRNA expression and IHC localization of its co-receptor Ret in the trigeminal ganglion of postnatal Day 0 mice. We found that approximately 70% of Ret-immunoreactive neurons possessed GFRalpha2 mRNA and virtually all GFRalpha2-expressing neurons contained Ret-immunoreactive protein. Finally, we used paraformaldehyde-fixed, paraffin-embedded sections and a monoclonal antibody against neuron-specific nuclear antigen (NeuN) to demonstrate the neuronal specificity of GFRalpha2 mRNA expression in adult mouse brain. This multi-labeling technique should be applicable to a wide variety of tissues, antibodies, and probes, providing a relatively rapid and simple means to compare mRNA and protein localization.     

Myosin and actin containing cells in the human postnatal thymus. Ultrastructural and immunohistochemical findings in normal thymus and in myasthenia gravis.

Samples of normal human thymus of different ages (4-63 years old) were studied by immunofluorescence microscopy (using antibodies to smooth muscle myosin, to actin from the chicken gizzard, and antibodies to myosin from human striated muscle) as well as by routine electron microscopy. Thymus tissue from myasthenia gravis patients was also investigated for comparative reasons. Epithelial cells reacted with anti-smooth, but not with anti-striated muscle myosin, whereas myoid cells reacted with antibodies to striated, but not to smooth muscle myosin. Both epithelial and myoid cells displayed a strong immunoreactivity with antiactin. Corresponding to this immunoreactivity, both cell types contained bundles of thin, actin-like filaments. Myoid cells occurred in the rounded and elongated variety, and they were a normal constituent of all thymuses investigated in this study. Ultrastructurally, this non-innervated, striated muscle-like cell type possessed bundles of thin and thick filaments as well as Z lines in a rather disorganized arrangement, resembling striated muscle after denervation or various other pathologic conditions. There were no overt differences in the number and structure of myoid cells between healthy and myasthenic patients.     

Localization of alpha 1-microglobulin (HC protein) in normal human tissues: an immunohistochemical study using monoclonal antibodies

Summary Alpha-1-microglobulin is a low molecular weight (approximately 30 000 d) glycoprotein present in biological fluids. It is heterogeneous in charge. A monoclonal antibody was used to investigate the tissue distribution of the protein in normal human tissues and cell lines by indirect immunofluorescence and immunoperoxidase techniques. The protein was demonstrable in cells of the monocyte-macrophage lineage, in thymus and T cell dependent areas of spleen, lymph node and tonsils. It was detected in several lymphoid or nonlymphoid cell lines but not in peripheral blood lymphocytes. The microglobulin was also detectable in the cytoplasm of hepatocytes. Finally, it was observed in glandular secretions (sudoral glands and mucosal glands of the digestive tract) where it may be associated with IgA. Possible explanations for the highly divergent results previously reported with polyclonal antisera to ₁ microglobulin are discussed.     

Influence of phallotoxins and metal ions on the rate of proteolysis of actin

The rate of proteolytic degradation of rabbit skeletal muscle actin by trypsin, alpha-chymotrypsin, and, mainly, subtilisin was followed by dual wavelength spectroscopy at 285 nm by reference at 320 nm. Phalloidin and phallacidin, two toxic bicyclic heptapeptides from the mushroom Amanita phalloides, protect F-actin against degradation by the proteolytic enzymes. G-actin, which does not combine with phalloidin when maintained in the monomeric state by working at low ionic strength, and bovine serum albumin, which also has no affinity to the toxin, are hydrolyzed at the same rates in the presence or absence of phalloidin. The proteolysis of F-actin is distinctly retarded by KCl alone, i.e., without phalloidin, whereas Mg2+ or Ca2+ as sole cations permit a rather high rate of hydrolysis. An even faster degradation of F-actin by subtilisin is observed in the presence of Mg2+ plus cytochalasin B. Adenosine diphosphate and triphosphate have no influence on the rate of the enzymatic degradation. The S sulfoxide of phalloidin, the nontoxic diastereomer of the toxic R form, exerts only a limited inhibitory effect on the enzymatic hydrolysis; secophalloidin, another nontoxic derivative, which does not bind to F-actin has practically no effect.     

Direct genomic fluorescent on-line sequencing and analysis using in vitro amplification of DNA.

In vitro amplification of genomic DNA and total RNA, as well as recombinant DNA, using one fluorescently labelled and one unlabelled primer during amplification, together with on-line analysis of the products on the EMBL fluorescent DNA sequencer, is described. Further is reported direct sequencing of fluorescently labelled amplified probes by solid-phase chemical degradation, without subcloning and purification steps involved. At present up to 350 bases in 4 hours are determined with this technique. The fluorescent dye and its bond to the oligonucleotide are stable during the amplification cycles, and do not interfere with the enzymatic polymerization. High sensitivity of the detection device, down to 10(-18) moles, corresponding to less than 10(6) molecules makes possible analyses of the non-radioactive amplified probes after only 10 amplification cycles, starting with about 5 x 10(4) copies of recombinant DNA.     

Localization of urotensin-II immunoreactivity in normal human kidneys and renal carcinoma.

Human urotensin-II (U-II) is a cyclic 11-amino-acid residue peptide with a wide range of vasoactive properties dependent on the anatomic site and the species studied. The purpose of this study was to determine the localization of human U-II in normal human kidneys and in renal carcinoma. Normal human kidneys (n=11) and eight cases of clear-cell carcinoma were immunostained with a polyclonal antibody to human U-II. In normal human kidneys, U-II was mostly present in the epithelial cells of tubules and ducts, with greater intensity in the distal convoluted tubules. Moderate U-II immunoreactivity was seen in the endothelial cells of renal capillaries, but only focal immunoreactivity was found in the endothelial cells of the glomeruli. No staining was found in the veins. All tumors expressed moderate U-II immunoreactivity in the cancer cells and vasculature. Here we demonstrate abundant expression of U-II in normal human kidneys and renal carcinoma. These findings suggest that the vasoactive and growth-mediator peptide U-II may contribute to the pathophysiology of the human renal system.     

Localization of gamma-glutamyl transpeptidase in human sweat glands: an immunohistochemical study using a monoclonal antibody

We studied the distribution of gamma-glutamyl transpeptidase (gamma-GT) by use of a monoclonal antibody (MAb) against human kidney gamma-GT in human sweat glands. In the eccrine sweat gland, the enzyme was localized along the luminal membrane and small apocrine extrusions of the superficial cells of the secretory portion. The intercellular canaliculi between basal cells were occasionally immunoreactive. In the secretory portion of the apocrine gland, luminal membrane and apocrine extrusions of various sizes and stages at the apices of the secretory cells exhibited positive reactions. Immunoreaction was also seen in the Golgi area of the cuboidal secretory cells. No positive reaction was observed in the myoepithelial cells of either gland or in the excretory duct cells.     

Localization of proinsulin and insulin in human insulinoma: preliminary immunohistochemical results

We have carried out an immunohistochemical investigation of 15 human insulinomas applying monoclonal antibodies specifically recognizing proinsulin and insulin. Our results demonstrate that the epitopes unique to proinsulin and insulin can be detected with the respective monoclonal antibodies using the protein A-gold technique after routine formaldehyde fixation and paraffin embedding of the tissues. The immunostaining pattern for proinsulin and insulin in the insulinomas was different from the observed in B cells of pancreatic islets present in the adjacent normal pancreas. Furthermore, the pattern of immunostaining was found to vary from tumor to tumor. These findings strongly suggest the possibility of a disturbed proinsulin to insulin conversion in human insulinomas.     

Autoregulatory control of actin synthesis in cultured rat hepatocytes.

ADP-ribosylation of actin by Clostridium botulinum C2 toxin resulted in a depolymerization of filamentous F-actin and an increase of monomeric G-actin in cultured hepatocytes. Simultaneously the de novo synthesis of actin was largely reduced, while the synthesis of albumin and of other proteins was not significantly impaired. The specific decrease of actin mRNA to 30% of the control indicates a down-regulation of actin synthesis at a pretranslational level. On the other hand, treatment with the mycotoxin phalloidin resulted in an increase of F-actin and a decrease of monomeric G-actin. Under this condition the de novo synthesis of actin was specifically enhanced and the level of actin mRNA was increased to 600% of the control. The data suggest an autoregulatory control of the actin synthesis.     

Localization and organization of actin in melanophores

Melanophores of the angelfish, Pterophyllum scalare, were studied in an attempt to demonstrate the existence of actin in these cells although microfilaments had previously not been found. By use of a variety of procedures, including immunofluorescence microscopy of intact and detergent-extracted cells, transmission electron microscopy, high voltage electron microscopy of whole-mount preparations, and labeling with heavy meromyosin-subfragment 1, the presence of a loose cortical mesh of actin filaments is demonstrated. In addition, a more parallel array of filaments is detected in microspike- and microvillus-like surface projections. There seem to be no changes in the arrangement of these filaments as a function of the state of pigment distribution. No actin filaments could be found in association with pigment granules or microtubules in more central cell portions. For reasons presently unknown, the preservation of the cortical filament network in lysed cell preparations depends strongly on the presence of an intact microtubular system. The involvement of this subplasmalemmal actin filament network in pigment granule transport remains unclear.     

Occurrence of alpha-fetoprotein-containing hepatocytes in human embryos and fetuses: an immunohistochemical study using the light and ultrastructural immunoperoxidase methods

The occurrence of alpha-fetoprotein (AFP)-containing hepatocytes in 12 human embryos and fetuses ranging from 30-32 days of estimated ovulation age (Streeter's horizon XIV) to 16-17 weeks of estimated menstrual age was investigated using the direct (horseradish peroxidase (HRP)-labeled anti-human AFP horse IgG(Fab')2) and/or indirect immunoperoxidase methods. Under light microscopy, the AFP-containing hepatocytes were successfully demonstrated in paraffin-embedded liver tissues fixed with 4% paraformaldehyde(PFA)-picric acid solution containing 0.5% glutaraldehyde (GA). As a result of the studies of the human fetal livers at different developmental stages, only a small number of AFP-containing hepatocytes were initially identified immunohistochemically at the stage of Streeter's horizon XIX. Ultrastructural immunohistochemistry (the block-staining method using anti-human AFP horse IgG(Fab')2) revealed that the immunoreactive products against AFP were demonstrated on the ribosomal granules of the rough endoplasmic reticulum (rER), outer nuclear envelopes, free ribosomes, and Golgi's apparatus, and also in the cisternal lumina of the ER. No reactive products were noted in the nuclei or mitochondria. Our observations confirmed the presence of AFP-producing ability of the hepatocytes and the ultrastructural localization of the sites of protein synthesis in the early stage of development of human livers. Furthermore, we describe the extreme usefulness of the block-staining method for demonstrating the subcellular localization of AFP using HRP-labeled reduced anti-AFP antisera on liver tissues fixed with 4% PFA-picric acid solution containing 0.5% GA.     

Cadmium induces mitochondria-dependent apoptosis of normal human hepatocytes

The heavy metal cadmium, an environmental pollutant, has been widely demonstrated to be toxic, in particular for liver. In murines, cadmium induces apoptosis of hepatocytes and hepatomas. In human cells, apoptosis induced by cadmium has been exclusively demonstrated in tumoral cell lines. Nothing was known in normal liver, in vitro or in vivo. In the present study, we examined the effects of cadmium in nonmalignant human hepatocytes. For that purpose, we investigated whether cadmium was able to induce apoptosis of normal human hepatocytes (NHH) in primary culture and of a SV40-immortalized human hepatocyte (IHH) cell line. Treatment of IHH and NHH with cadmium induced the presence of a sub-G₁ population at 10 and 100 μmol/L, respectively. DAPI staining of both cell types treated with cadmium 100 μmol/L revealed the induction of nuclear apoptotic bodies, supporting the hypothesis of apoptosis. In IHH and NHH, cadmium 100 μmol/L induced PARP cleavage into a 85 kDa fragment. In order to investigate the involvement of mitochondria in cadmium-induced apoptosis, we measured the mitochondrial membrane potential (Δ_Ψm). We observed that in IHH and NHH, cadmium 100 μmol/L induced a decrease of Δ_Ψm. As expected, cadmium under the same conditions enhanced caspase-9 and caspase-3 activities. In addition, cadmium from 1 to 100 μmol/L induced the expression of p53 and phosphorylation of its Ser15 in IHH and NHH. In conclusion, we showed in this study that human hepatocytes were sensitive to cadmium and apoptosis induced at concentrations suggested in the literature to inhibit p53 DNA-binding and DNA repair.     

Tetranectin immunoreactivity in normal human tissues. An immunohistochemical study of exocrine epithelia and mesenchyme

A recently discovered human plasma protein, tetranectin (TN), which has previously been demonstrated immunohistochemically within various endocrine tissues, was in this study identified in an additional number of epithelial and mesenchymal cells by two polyclonal antibodies and one monoclonal using the conventional immunoperoxidase staining technique and a modification of the CLONO-GLAD procedure. TN was found in endothelial and epithelial tissues, particularly in cells with a high turn-over or storage function such as gastric parietal and zymogenic cells, absorptive surface epithelium of the small intestine, ducts of exocrine glands and pseudostratified respiratory epithelium. Also mesenchymal cells produced a TN positive staining reaction, which was most conspicuous in mast cells, but also present in some lymphocytes, plasma cells, macrophages, granulocytes, striated and smooth muscle cells and fibroblasts. SDS-PAGE and Western blotting analysis of cultured human embryonal fibroblasts (WI-38) showed that the cells besides TN contain another protein with a molecular weight of 82,000. As this protein, however, reacted with our affinity purified antibodies it probably represents a precursor of TN or a protein with a molecular weight of approximately 60,000, which is covalently linked to TN. This and the fact that TN shows amino acid sequence homologies to the carboxyterminal part of the asialo-glycoprotein receptor and a cartilage proteoglycan core protein as well a binding affinity to plasminogen points to TN as being part of a larger molecule, which possibly has been cleaved by proteolysis at the cellular site and then passed into the blood, where it polymerizes into a tetramer.     

Studies on the structure of actin gels using time correlation spectroscopy of fluorescent beads.

Fluorescence correlation spectroscopy (FCS) has been used to measure the diffusion of fluorescently labeled beads in solutions of polymerized actin or buffer. The results, obtained at actin concentrations of 1 mg/ml, show that small beads (0.09 micron in diameter) diffuse nearly as rapidly in the actin gel as in buffer, whereas the largest beads tested (0.5 micron in diameter) are immobilized. Measured autocorrelation times for motions of beads with intermediate sizes show that the diffusion is retarded (relative to buffer) and that the time behavior cannot be represented as a single diffusive process. In addition to the retarded diffusion observed over distances > 1 micron, 0.23-micron beads also show a faster motion over smaller distances. Based on the measured rate of this faster motion, we estimate that the beads may be constrained within a cage approximately 0.67 micron on a side, equal to a filament length of approximately 250 subunits. Fluorescence correlation spectroscopy measurements made in the same small spot (radius of 1.4 microns) of the gel vary over time. From the variations of both the autocorrelation functions and the mean fluorescence, we conclude that, corresponding to a spatial scale of 1.4 microns, the actin gel is a dynamic structure with slow rearrangement of the gel occurring over periods of 20-50 s at 21-22 degrees C. This rearrangement may result from local reorganization of the actin matrix. Data for the retardation of beads by the actin gel are consistent with a detailed theory of the diffusion of particles through solutions of rigid rods that have longitudinal diffusion coefficients much less than that of the particles (Ogston, A. G., B. N. Preston, and J. D. Wells. 1973. Proc. R. Soc. Lond. A. 333:297-316).     

Localization of NTPDase1/CD39 in normal and transformed human pancreas.

Elevated levels of extracellular ATP have been observed in many tumors. We have localized NTPDase1/CD39, one of the principal extracellular nucleotide-hydrolyzing enzymes, in normal and cancerous human pancreas. NTPDase/E-ATPDase activity was demonstrated with an enzyme histochemical technique on cryosections of human pancreas. Acinar and duct epithelial cells were devoid of E-ATPDase activity in both normal and transformed tissue. Endothelial cells and smooth muscle around blood vessels and larger ducts showed strong activity. Nerves, connective tissue, and the beta-cells of the islets were also stained. In cancerous tissue this activity was diminished in the smooth muscle around the ducts and was absent from newly formed connective tissue. Immunostaining for CD39 supported these results but revealed the presence of inactive CD39 in the duct epithelial cells. We hypothesize that the significantly diminished activity of NTPDase1 in the tissues surrounding the ducts may be associated with the processes that lead to tumor formation in human pancreas.     

大丽轮枝菌微丝荧光标记载体构建及应用

微丝在真菌生长发育、胞质分裂等生命过程中具有重要功能。通过农杆菌介导遗传转化方法,将荧光mCherry标记微丝的表达载体pSULPH-Lifeact-mCherry转入大丽轮枝菌(Verticillium dahliae Kleb.)野生型V592,获得稳定的微丝荧光标记菌株V592/Lifeact-mCherry,并检测了其生物学表型和孢子萌发、菌丝生长等过程中的微丝荧光动态变化。结果表明:微丝荧光标记菌株的菌落形态、生长速率、产孢量、萌发率等表型与野生型没有显著差异;且可以观察到微丝荧光信号在分生孢子和菌丝的顶端及隔膜都有清晰定位,同时对该菌株隔膜形成过程微丝动态观察发现,微丝参与胞质分裂进程中肌动球蛋白收缩环CAR (Contractile actomyosin ring)的形成。微丝荧光标记菌株可用于微丝在真菌发育中的动力学研究,这为深入研究微丝在真菌发育及致病过程中的作用机制提供理论与实践支撑。