Immunocytochemical localization of gut-associated circulating anodic antigen in Schistosoma japonicum

The localization of the gut-associated circulating anodic antigen in Schistosoma japonicum adults was revealed by means of the immunofluorescence and a peroxidase-anti-peroxidase method with the electron microscope. The reaction sites were confined to amorphous material in the cecal lumen. The cecal lumen generally was infolded with lamellae. The antigenic material appeared to be secreted by the rough endoplasmic reticulum, probably through the Golgi apparatus, into the lumen. Observations of male and female worms showed that there was a clear difference between the sexes in antigen concentration. The thick epithelium of the female worm, with well-developed cisternae on the endoplasmic reticulum, produced a lot more antigen than the male. Positive staining with ruthenium red confirmed that the antigenic material was a negatively charged polysaccharide as had been previously reported.     

Quantification of Indole-3-Acetic Acid in Dark-Grown Seedlings of the Diageotropica and Epinastic Mutants of Tomato (Lycopersicon esculentum Mill.)

Endogenous indoleacetic acid (IAA) levels were examined in 7-day-old, dark-grown tomato seedlings (Lycopersicon esculentum Mill. cv VFN8), and in two single-gene mutants, Epinastic and diageotropica. Gas chromatography-mass spectrometry was employed to quantify IAA using ¹³C₆-[benzene ring]indoleacetic acid as internal standard. IAA concentrations ranged from 89 to 134 nanograms per gram dry weight and were not significantly different for the three genotypes. Ethylene over-production by dark-grown Epi seedlings is not likely to result from increased IAA. Assuming similar recovery percentages for each genotype, indole-3-ethanol, a purported storage form of IAA, was identified by GC-MS and found to be more prevalent in the parent tomato, VFN8, with only trace amounts observed in Epi. No IEt was detected by high performance liquid chromatography/fluorescence in dgt (detection limit >100 picograms).     

Pituitary adenylate cyclase activating polypeptide stimulates gallbladder motility in conscious dogs.

We investigated whether pituitary adenylate cyclase activating polypeptide (PA-CAP27 and PACAP38) had any effect on gallbladder motility in conscious dogs, in which force transducers were chronically implanted in the gastric antrum, duodenum and gallbladder. PACAP27 and PACAP38 were administered intravenously during the digestive and interdigestive states at doses of 30, 100 and 300 pmol/kg. By way of comparison, cholecystokinin octapeptide (CCK-OP) was administrated at doses of 3, 9 and 27 pmol/kg. As a result, each peptide evoked transient and tonic contractions both in the digestive and interdigestive states, and the effect on the motor index was dose dependent. PACAP27 and PACAP38 were 0.11 +/- 0.03 and 0.04 +/- 0.01 as potent as CCK-OP in the digestive state, and 0.18 +/- 0.04 and 0.02 +/- 0.01 in the interdigestive state, respectively, on a molar basis. Although PACAP27 and PACAP38 belong to the vasoactive intestinal polypeptide (VIP) family, intravenous administration of 300 pmol/kg of VIP had no effect on interdigestive gallbladder motility, but on the other hand inhibited gallbladder motility in the digestive state. The contractile effects of PACAP27 and PACAP38 were almost completely abolished by pretreatment with atropine or hexamethonium, but not with L364718. An in vitro study using canine gallbladder strips showed that PACAP27 and PACAP38 had no effect on spontaneous gallbladder motor activity evoked by electric field stimulation, CCK-OP or acetylcholine. It was concluded that PACAP27 and PACAP38 stimulate gallbladder motility in conscious dogs through a preganglionic cholinergic mechanism.     

OlpB, a new outer layer protein of Clostridium thermocellum, and binding of its S-layer-like domains to components of the cell envelope.

Several proteins of Clostridium thermocellum possess a C-terminal triplicated sequence related to bacterial cell surface proteins. This sequence was named the SLH domain (for S-layer homology), and it was proposed that it might serve to anchor proteins to the cell surface (A. Lupas, H. Engelhardt, J. Peters, U. Santarius, S. Volker, and W. Baumeister, J. Bacteriol. 176:1224-1233, 1994). This hypothesis was investigated by using the SLH-containing protein ORF1p from C. thermocellum as a model. Subcellular fractionation, immunoblotting, and electron microscopy of immunocytochemically labeled cells indicated that ORF1p was located on the surface of C. thermocellum. To detect C. thermocellum components interacting with the SLH domains of ORF1p, a probe was constructed by grafting these domains on the C terminus of the MalE protein of Escherichia coli. The SLH domains conferred on the chimeric protein (MalE-ORF1p-C) the ability to bind noncovalently to the peptidoglycan of C. thermocellum. In addition, 125I-labeled MalE-ORF1p-C was shown to bind to SLH-bearing proteins transferred onto nitrocellulose, and to a 26- to 28-kDa component of the cell envelope. These results agree with the hypothesis that SLH domains contribute to the binding of exocellular proteins to the cell surface of bacteria. The gene carrying ORF1 and its product, ORF1p, are renamed olpB and OlpB (for outer layer protein B), respectively.     

HPLC methods for detection of uniconazole-P in soils and plant tissues

High-performance liquid chromatographic (HPLC) methods have been developed for the detection of uniconazole-P [(E)-1-(4-chlorophenyl)-4,4,-dimethyl-2-(1,2,4-triazol-1-yl)-1-penten-3-ol; XE-1019; the active ingredient in Prunit and Sumagic] in soil and plant tissue samples. Methanolic extracts of soil and plant samples were dried to the aqueous phase, the pH adjusted to 11, and partitioned against methylene chloride. The methylene chloride phases were washed with pH 11 water and then passed through C-18 solid phase extraction (SPE) columns. The soil extracts were then dried and the residues taken up in 1 ml acetonitrile of which 20 l were injected directly onto a C-18 reverse phase analytical column for HPLC analysis. Plant tissue extracts were purified by partitioning and passing through a sequence of Florisil/C-18/Florisil SPE columns before HPLC analysis. Recovery of uniconazole-P was 70% from soils and 40% from plant tissues. Quantitative detection of 10 parts per billion (ppb) uniconazole-P in plant tissues and soil samples was feasible following these procedures. The soil cleanup procedures were also used to detect uniconazole-P in leachates collected from container-grown plants.     

Pituitary adenylate cyclase activating polypeptide provokes cultured rat chromaffin cells to secrete adrenaline.

Pituitary adenylate cyclase activating polypeptide (PACAP) provoked the rat chromaffin cells to secrete adrenaline. Within 20 min, the amount of adrenaline secreted by PACAP (10(-8) M) was as much as that caused by acetylcholine (10(-4) M). PACAP, but not acetylcholine, induced a long-term (over 120 min) increase in secretion of adrenaline. PACAP also activated adenylate cyclase and elevated cytosolic Ca2+ concentration. Furthermore, we found immunoreactive PACAP and PACAP binding sites in the rat adrenal medulla. These results suggest that PACAP has an important role in stimulating secretion of adrenaline in the adrenal medulla.     

Role of hydrosulfide ions (HS-) in methylmercury resistance in Saccharomyces cerevisiae.

Methylmercury-resistant mutants were obtained from Saccharomyces cerevisiae. They were divided into two complementation groups, met2 (homoserine O-acetyltransferase deficiency) and met15 (enzyme deficiency unknown), as reported previously. It was found that met15 was allelic to met17 (O-acetylserine and O-acetylhomoserine sulfhydrylase deficiency). Methylmercury toxicity was counteracted by exogenously added HS-, and both met2 and met17 (met15) mutants overproduced H2S. On the basis of these results, we conclude that met2 and met17 (met15) cause accumulation of hydrosulfide ions in the cell and that the increased level of hydrosulfide is responsible for detoxification of methylmercury.