Instrumentation and applications of an automated C-terminal fragment peptide fractionator for C-terminal sequence analysis of proteins

A novel automated C-terminal fragment peptide fractionator has been constructed. Digests with lysyl endopeptidase were covalently immobilized on p-phenylene diisothiocyanate polymer beads. Only the C-terminal fragment, which contains no lysyl residue, was liberated by cleavage at the first peptide bond of the immobilized fragment peptides with trifluoroacetic acid, and it was automatically collected. The whole procedure was automatically and precisely performed under microprocessor control in a nitrogen atmosphere. The resulting fragment was sequenced without further purification. Sequences of both N- and C-terminal regions can be routinely obtained for ca. 100 pmol samples by the use of a conventional automated Edman-type protein sequencer.

Biochemical and enzymological study of lactate dehydrogenase isoenzymes from commercial quality control sera and several animal tissue sources

We assayed the isoenzymes of lactate dehydrogenase (EC 1.1.1.27) in commercial quality control sea and several animal tissue extracts, using electrophoresis. We compared the Km values and activation energies of the isoenzymes, in order to find suitable animal tissue sources with a similar isoenzyme profile to that of human serum lactate dehydrogenase. Some of the control sera contained only one isoenzyme fraction corresponding to porcine heart isoenzyme-1 or chicken heart isoenzyme-1, which showed essentially no changes of enzyme activity as a function of pyruvate substrate concentration. Other control sera, which contained isoenzymes from human red cells haemolysates, or from animal tissue extracts with a human serum matrix, showed significant changes of enzyme activity was a function of substrate concentration, and showed different Km values and activation energies from those of human serum. Of the serum and tissue samples from several animal sources, rat heart and kidney extracts showed the greatest similarity to human serum, with respect to the electrophoretic pattern and the Km, pH optimum and activation energy of lactate dehydrogenase isoenzymes.

Attenuation of vasoactive intestinal peptide enhancement of colon carcinogenesis by ornithine decarboxylase inhibitor

The effects of combined administration of vasoactive intestinal peptide (VIP) and the ornithine decarboxylase (ODC) inhibitor, 1,3-diaminopropane (DAP), on development of colon tumors induced by azoxymethane (AOM), on ODC activity of the colon wall, and on the labelling index of colon epithelial cells were investigated in inbred Wistar rats. Rats received weekly subcutaneous injections of AOM for 10 weeks and subcutaneous injections of VIP every other day and drinking water containing DAP (2.5 milligrams) ad libitum until the end of the experiment at week 45. Administration of VIP significantly increased the incidence of colon tumors at week 45. It also resulted in significant increases in colon ODC activity and in the labelling index during administration of AOM, but not after its cessation. Administration of both DAP and VIP significantly reduced the enhanced colon carcinogenesis by VIP. The DAP significantly attenuated the VIP enhancement of colon ODC activity and of the labelling index during AOM administration. These findings indicate that ODC inhibition attenuated enhancement of colon carcinogenesis, and suggest that enhancement of colon carcinogenesis by VIP may be mediated through its polyamine biosynthesis.

Dependence of water conductivity on pressure and temperature in plant stems

The effects of pressure and temperature on water conductivity were examined in okra stem segments. Segments were incubated in various concentrations of sorbitol solution at various temperatures. Water was found to pass mainly through the lateral side of the segments. The shrinkage rate was found to be proportional to the difference in the water potential between the inside of the cells and the ambient solution, while the rate was inversely proportional to the viscosity of water, which is a function of temperature. The nature of the media for water conductivity was found to be consistent with Darcy's law and with Hagen-Poiseuille's law with a rough approximation. An attempt was made to estimate the size of the water path. Okra stem segments were incubated with and without the plant hormone auxin before transference to sorbitol solution. Shrinkage rates of segments showed that auxin caused an increase in water conductivity and thus the size of the water path.

DNA diversity among isolates of Campylobacter jejuni detected by PCR-based RAPD fingerprinting

A PCR-based randomly amplified polymorphic DNA method was used to amplify Campylobacter jejuni DNA using a single oligonucleotide primer derived from either a homologous source or from Mycoplasma gallisepticum. The method was able to detect the heterogeneity of amplified DNA from human, chicken and turkey sources and can be used as a tool to study the epidemiology of Campylobacter jejuni infection.

Correlation between serum prolactin levels and hepatocellular tumorigenesis induced by 3'-methyl-4-dimethylaminoazobenzene in mice

Ovariectomy at 1 month of age promotes development of hepatocellular adenomatous nodules in female C57BL/6 x DS-F1 mice treated neonatally with 3'-methyl-4-dimethylaminoazobenzene (3'-Me-DAB). Implantation of oestradiol-17 beta (E2) pellets at 1 month of age suppresses nodule development. Since E2 increases serum levels of prolactin, high serum levels of prolactin in mice that have received implants of E2 pellets may play a role in the suppression of hepatocellular tumorigenesis. Therefore, to investigate the role of prolactin in hepatocellular tumorigenesis, we examined development of adenomatous nodules in female mice that had been treated neonatally with 3'-Me-DAB and had undergone ovariectomy at 1 month of age, under various serum levels of prolactin. Treatment of these mice with perphenazine (dopamine antagonist) from 6 months of age or transplantation of pituitary glands under the renal capsule at 6 months of age markedly increased serum levels of prolactin and significantly suppressed the incidence of adenomatous nodules at 12 months of age. Implantation of E2 pellets at 1 month of age increased serum levels of prolactin to a greater extent and further decreased the incidence of adenomatous nodules. Treatment of mice that had received implants of E2 pellets at 1 month of age with bromocriptine (dopamine agonist) from 6 months of age decreased serum levels of prolactin, and was accompanied by an increase in the incidence of nodules. The present results showed that an increase in serum levels of prolactin was accompanied by a decrease in incidence of liver tumours induced by 3'-Me-DAB in mice, suggesting a suppressive effect of prolactin on liver tumorigenesis in mice. Thus, it is possible that the suppressive effect of oestrogen on liver tumorigenesis in mice is mediated, at least in part, by prolactin.

Possible role of herpes simplex virus in the origin of Posner-Schlossman syndrome

PURPOSE/METHODS

We conducted this study to determine if the herpesviruses are possible etiologic agents in Posner-Schlossman syndrome. We aspirated aqueous humor samples from patients during acute attacks of the syndrome. Ten normal aqueous humor specimens from patients undergoing cataract surgery were used as controls. DNA was extracted and subjected to polymerase chain reaction amplification and Southern blot hybridization.

RESULTS/CONCLUSION

All three specimens were positive for amplified genomic fragments of herpes simplex virus and negative for varicella-zoster virus and cytomegalovirus. Ten normal aqueous specimens were negative for all three. Herpes simplex virus may play a role in the origin of Posner-Schlossman syndrome.

Clinical significance of reverse redistribution phenomenon after coronary artery bypass grafting

The reverse redistribution (RR) phenomenon is a decrease in thallium 201 uptake during redistribution compared with 201Tl uptake immediately after exercise. We evaluated RR in 23 patients after coronary artery bypass grafting. Postoperative RR was present in 48% and was significantly more common in patients with a history of myocardial infarction (62%). The patients were classified according to the presence (+) or absence (-) of RR. An analysis of left ventricular wall motion showed significant improvement after coronary artery bypass grafting in the RR+ group (n = 12) but not in the RR- group (n = 11). Quantitative myocardial viability was evaluated using the defect volume ratio, mean defect severity, and defect severity index. The preoperative defect volume ratio was higher in the RR+ group than in the RR- group (p < 0.05). In the RR- group, no improvement in these indices was observed after operation. In contrast, the RR+ group showed significant improvement in all three indices (p < 0.05). These results indicate that after coronary artery bypass grafting, an adequate blood supply to the remaining myocardium may induce RR. This phenomenon, therefore, may be a significant indicator of postoperative myocardial viability.

In ovo pathogenicity of Mycoplasma iners strain Oz

Embryonating chicken eggs were inoculated with the type strain (PG30) of Mycoplasma iners and with an additional strain of this species designated Oz. Marked gross and histopathologic lesions were observed in the embryos inoculated with strain Oz but not in those infected with strain PG30. Gross lesions were manifested by an enlargement of one or more joints that often contained a caseous exudate, both in the joint space and periarticularly. In the order of frequency, the most common lesions were found in the following joints: tibiotarsal, distal humoral, proximal humoral, femoral, mandibular, tibiofemoral, and phalangial. Similar caseous foci were also seen in the liver and, rarely, in the heart. Histologically, the most prominent lesion found in the joints and viscera was a multifocal caseous necrosis accompanied by the formation of granulomas. Many joints had progression of the inflammatory cells outward from the joint spaces along the periosteal surfaces, and the articular cartilages contained erosions and focal necrosis.

Depression of hepatic cytochrome P450 monooxygenases after chronic environmental tobacco smoke exposure of young ferrets

Six-week-old ferrets were exposed head-only to clean air or environmental tobacco smoke (ETS) for 2 h/day, 5 days a week for a total of 8 weeks. Exposure to ETS caused a significant reduction in the levels of hepatic microsomal cytochrome P450 and P450 reductase activity in both the male and female ferrets. The content of cytochrome b5 and the activity of its reductase were significantly reduced in the hepatic microsomes of female ferrets. 7-Ethoxycoumarin O-deethylase activity and cytochrome P450 (CYP) 1A protein were markedly decreased in the hepatic microsomes of both the male and female ferrets after ETS exposure. In accord with the downregulation of P450, total metabolites formed from benzo[a]pyrene were significantly reduced in the liver homogenates of ETS-exposed animals. Similarly, sum total of free (+)-anti-benzo[a]pyrene-7,8-dihydrodiol-9,10-epoxide, glutathione conjugates and DNA-bound metabolites formed from precursor (-)-7R-trans-benzo[a]pyrene-7,8-dihydrodiol showed marked reduction in both the male and female ferrets after ETS exposure in a dose-response manner. This is the first report showing downregulation of hepatic P450 and accompanying benzo[a]pyrene metabolism after tobacco smoke exposure which apparently occurred after an initial upregulation of these parameters (Rasmussen et al. (1994) FASEB J. 8, A122).

Functional wild-type and carboxyl-terminal-tagged rat substance P receptors expressed in baculovirus-infected insect Sf9 cells

The rat substance P (SP) receptor (SPR) was expressed in insect Sf9 cells by infection with recombinant baculovirus. The receptor bound SP with high affinity (KD = 360 pM) and had a rank order of affinity of SP > neurokinin A > neurokinin B. Ligand activation of the receptor resulted in an increase in both inositol lipid hydrolysis and intracellular Ca2+ concentration ([Ca2+]i). However, high-level expression of the receptor, in the absence of ligand, was correlated with increased basal turnover of inositol lipids and an elevated rate of Ca2+ influx. These results demonstrate that the Sf9 cells provide a suitable environment for the high-level expression of a functionally active SPR. Two carboxy-terminal epitope-tagged receptors (SPR-KT3 = SPR-TPPPEPET, COOH; SPR-Glu = SPR-EEEEYMPME, COOH) were also expressed. The affinity of the KT3-tagged receptor for ligand was similar to that of the wild-type receptor (KD = 405 pM), and that of the Glu-tagged receptor was slightly lower (KD = 1,082 pM). The high-affinity SP binding site of all three receptors was sensitive to guanosine 5'-O-(3-thiotriphosphate) pretreatment. The maximal signal-transducing ability of the epitope-tagged receptors was comparable to that of the wild-type receptor ([Ca2+]i rise as a percentage of wild-type: SPR-KT3, 80-100%; SPR-Glu, 88-100%). These data show that heterologous expression in the baculovirus system results in high expression of functional wild-type and tagged receptors.

Activation of trypsinogen in experimental models of acute pancreatitis in rats

Trypsinogen activation peptide (TAP) concentration and alpha 2-macroglobulin-trypsin complex (alpha 2M-T) activity were measured in two experimental models of acute pancreatitis in rats to evaluate the significance of activation of trypsinogen in acute pancreatitis. TAP concentration and alpha 2M-T activity in serum rose significantly in trypsin-taurocholate-induced hemorrhagic acute pancreatitis, while in cerulein-induced edematous acute pancreatitis they did not rise in spite of a similar increase in immunoreactive trypsin. When rats in trypsin-taurocholate-induced pancreatitis were treated by protease inhibitor (FUT-175; nafamostat mesilate; FUT group), alpha 2M-T activity in serum was significantly lower than that in nontreated controls (mean +/- SEM, 20.8 +/- 1.43 U/L in the FUT group vs 79.1 +/- 24.5 in controls; p < 0.01). The survival rate at 24 h was significantly improved in the FUT group compared with the controls (70 vs 43%; p < 0.05). The increase in TAP concentration in the FUT group was similar to that in controls. The TAP concentration in pancreatic tissue at 24 h was significantly (p < 0.01) lower in the survival group (7.8 +/- 0.8 ng/ml) than in the lethal group (25.9 +/- 3.7 ng/ml). Activation of trypsinogen and its subsequent enzyme activity play an important role in the evolution of severe acute pancreatitis.

Primary structure of human amphiphysin, the dominant autoantigen of paraneoplastic stiff-man syndrome, and mapping of its gene (AMPH) to chromosome 7p13-p14

Amphiphysin is a protein peripherally associated with synaptic vesicles. It is expressed in many neurons, certain endocrine cell types, and spermatocytes. Autoantibodies against amphiphysin occur in patients afflicted with a rare neurologic autoimmune disease, paraneoplastic Stiff-Man syndrome. To provide a basis for the understanding of anti-amphiphysin autoimmunity, we have cloned cDNAs and determined the primary structure of human amphiphysin. Comparison with chicken amphiphysin defines domains of low and high amino acid sequence conservation. As a candidate for heritable disorders of the nervous system, endocrine tissues or male fertility, the human amphiphysin gene was mapped to chromosome 7, region p13-p14.

In vitro selection of RNA aptamers that can bind specifically to Tat protein of HIV-1

The Tat protein of human immunodeficiency virus interacts specifically with its target RNA sequence, TAR, and activates viral gene expression at the early stage of infection. Here, we have used in vitro genetic selection strategy to determine what sequence or structural motifs might exist between RNA's that interact specifically with the Tat protein. Starting from a RNA pool that has a 120 base random sequence core, aptamers that bind specifically to the Tat protein were selected by repeating 11 rounds of selection and amplification. A comparative analysis of 64 aptamers that were isolated from the 11th generation revealed two main sequence classes. Interestingly, one of these two classes of aptamers had minimum of one U residues in bulge loop and 2 specific adjacent base pairs. This region is very much homologous to the core sequence of TAR RNA that is essential for the specific Tat-TAR interactions. Further analyses of the sequences from the 11th generation should reveal what kind of RNA structures are required in order to show a high affinity for the Tat protein.

Scanning electron microscopic observations on gastric mucus secretion in rats, and the effects of tetraprenylacetone

Mucus secretion in the gastric mucosa of rats was studied with a scanning electron microscope. After stimulation, two types of mucus secretion were observed: exocytosis and apical expulsion. Prolonged administration of tetraprenylacetone (TPA) significantly increased the number of mucus-secreting cells in both the gastric corpus and antrum 12 h after the last administration of TPA. In the secreting cells, apical expulsion was significantly more frequent among TPA-treated than in untreated rats. TPA also significantly increased the hexosamine concentration in both gastric corpus and antrum. These findings indicate that TPA stimulates both the content and the secretion of gastric mucus, and that its secretion is chiefly through apical expulsion.

Proadrenomedullin N-terminal 20 peptide (PAMP), an endogenous anticholinergic peptide: its exocytotic secretion and inhibition of catecholamine secretion in adrenal medulla

In cultured bovine adrenal medullary cells, stimulation of nicotinic receptors by carbachol evoked the Ca(2+)-dependent exocytotic cosecretion of proadrenomedullin N-terminal 20 peptide (PAMP) (EC50 = 50.1 microM) and catecholamines (EC50 = 63.0 microM), with the molar ratio of PAMP/catecholamines secreted being equal to the ratio in the cells. Addition of PAMP [1-20]NH2 inhibited carbachol-induced 22Na+ influx via nicotinic receptors (IC50 = 2.5 microM in a noncompetitive manner and thereby reduced carbachol-induced 45Ca2+ influx via voltage-dependent Ca2+ channels (IC50 = 1.0 microM) and catecholamine secretion (IC50 = 1.6 microM). It did not alter high K(+)-induced 45Ca2+ influx via voltage-dependent Ca2+ channels or veratridine-induced 22Na+ influx via voltage-dependent Na+ channels. PAMP seems to be a novel antinicotinic peptide cosecreted with catecholamines by a Ca(2+)-dependent exocytosis in response to nicotinic receptor stimulation.