An amphicrine pancreatic cell line: AR42J cells combine exocrine and neuroendocrine properties.

The permanent cell culture line AR42J, derived from a rat pancreatic acinar carcinoma, is widely used for functional studies of exocrine pancreatic acinar cells. We now present evidence that these cells are amphicrine in that they contain zymogen granules as well as small (40-80 nm) neuroendocrine (NE) vesicles and typical neurotransmitters. Using the small NE vesicle-specific markers synaptophysin and "protein S.V.2", including synaptophysin cDNA probes, we have found that AR42J cells synthesize these proteins and contain vesicles harboring these proteins with biophysical properties similar to those of small NE vesicles. NE properties of these cells are further indicated by the presence of considerable amounts of stored amino acids (gamma-aminobutyric acid (GABA), glycine, glutamate) and by the presence of the GABA-synthesizing enzyme, glutamic acid decarboxylase. Finally, intermediate filament (IF) protein typing showed only cytokeratins 8 and 18, indicating that AR42J cells possess an IF protein complement indistinguishable from that of acinar and islet cells. Our results document the unusual case of a permanent cell line with combined exocrine and neuroendocrine properties that may be indicative of a derivation from a cell with multipotential character.     

Staggerer-specific protein SP47: A unique species among age- and genotype-dependent cerebellar proteins

Genotype- and age-specific proteins are found in the developing cerebellum of wildtype and staggerer (sg/sg) mutant mice by analysis of silver-stained one- and two-dimensional protein patterns. The methods used are suitable for gross inspection of protein patterns without previous purfication, labeling, or immunochemistry. SP47, a polypeptide of 47 kD with a pI of 6.0, appears in the mature staggerer cerebellum, but not in the wildtype. SP47 is different from the astrocytic glial fibrillary acidic protein (GFAP) as shown by immunoblotting. Four polypeptides have been identified with distinct development- and genotype-dependent patterns in the cerebellum. Some of the changes are correlated with events during postnatal histogenesis.Abbreviations used CNS central nervous system - EDTA ethylenediaminetetraacetic acid - EGTA ethyleneglycol-bis-(-aminoethyl ether)-N,N,N,N-tetraacetic acid - GFAP glial fibrillary acidic protein - HEPES N-2-hydroxyethylpiperazine-N-2-ethanesulfonic acid - IEF isoelectric focussing - MAMAc methylazoxymethanol acetate - NP-40 nonidet P-40 - PBS phosphate buffered saline - PMSF phenylmethylsulfonylfluoride - SDS-PAGE sodium dodecyl sulfate polyacrylamide gel electrophoresis - SEM sucrose/EDTA/mercaptoethanol - TGS Tris HCl/gelatin/sodium chloride - Tris HCl tris(hydroxymethyl)aminomethane hydrochloride     

In situ lymphoid cells of mouse mammary tumors. IV. Comparison of functional activity of lymphoid cells separated from mammary tumors to that of spleen and lymph node cells of tumor-sensitized mice.

Lymphoid cells isolated form several types of mouse mammary tumors are capable of stimulating tumor cell growth or survival in MCT assays. Lymph node and spleen cells of mice bearing such a tumor are specifically cytotoxic to the tumor cells. Surgical removal of the tumor is followed in 4 to 7 days by the appearance of stimulatory capacity in spleens and lymph nodes. By day 10, cytotoxic cells specific for the sensitizing tumor are again detected. These reach a peak on day 13. By day 17 no reactivity is detectable. The functional distribution of tumor-reactive lymphoid cells is different between tumor masses and peripheral lymphoid organs.     

The reproductive system of Gastrotrichs

Summary A structural, ultrastructural and functional analysis is made of genital organs ofMacrodasys, a member of the hermaphroditic marine Gastrotricha. The gonads are paired, hermaphroditic and polarized into male and female regions. Male and female gametes are produced simultaneously. Fertilization is internal. Accessory organs consist of, from anterior to posterior, simple male pores, a seminal receptacle and spermatheca, and, a complex caudal organ. Copulation results in reciprocal cross insemination. Sperm transfer, however, is indirect. Autosperms are transferred externally from the male pores to the caudal organ while the animals are in copula. The caudal organ then functions as a penis conducting the autosperms into the partner's seminal receptacle. This unique mode of sperm transfer is discussed with reference to the lower Bilateria and the Metazoa.Abbreviations ans anus - ant antrum, antrum feminimum, uptake portion of caudal organ - ccl cap cells - cim circular muscles - eev egg envelope - egl epidermal glands - epd epidermal cells - gmo glandulomuscular portion of caudal organ - int intestine, gut - lgm longitudinal muscles - mpr male pores - npl neuropile - nrv nerve cells - ooc oocytes, eggs - phg pharyngeal gland cells - phx pharynx - ppr pharyngeal pores - rsp residual sperm - sdp secretory droplet - sgb Stempelgruben, piston-pits, probable chemosensory organ - spd spermatids - spm sperm - spt spermatheca - srp seminal receptacle, bursa - tub copulatory tube of glandulomuscular organ - vdf vasa deferentia This project was supported by a Postdoctoral Fellowship from the Smithsonian Institution, and National Science Foundation grants GB-42211, OCE 75-23781 AO1 and OCE 75-20227 AO2 to The University of No. Carolina and the Bermuda Biological Station     

Experimental proof for a signal peptidase I like activity in Mycoplasma pneumoniae, but absence of a gene encoding a conserved bacterial type I SPase

Although the annotation of the complete genome sequence of Mycoplasma pneumoniae did not reveal a bacterial type I signal peptidase (SPase I) we showed experimentally that such an activity must exist in this bacterium, by determining the N-terminus of the N-terminal gene product P40 of MPN142, formerly called ORF6 gene. Combining mass spectrometry with a method for sulfonating specifically the free amino terminal group of proteins, the cleavage site for a typical signal peptide was located between amino acids 25 and 26 of the P40 precursor protein. The experimental results were in agreement with the cleavage site predicted by computational methods providing experimental confirmation for these theoretical analyses.     

Acute effects of smoking and high experimental exposure to environmental tobacco smoke (ETS) on the immune system

Controversial results have been published on the immune response to cigarette smoking while the effects of exposure to environmental tobacco smoke (ETS) have not yet been reported. In a controlled study, acute effects of smoking and of a high environmental exposure to ETS on immunological parameters have been investigated. The study consisted of four experimental days, two control and two exposure days. On control days, 1 and 3, smokers (n=5) and nonsmokers (n=5) sat in an unventilated 45 m³ room for 8 h. On the exposure days, 2 and 4, each of the smokers smoked 24 cigarettes in 8 h, while the nonsmokers were exposed to the ETS generated by the smoking volunteers. Blood was drawn before and after each exposure session on all four experimental days for dosimetry of tobacco smoke exposure and determination of the immune response. Flow cytometry using monoclonal antibodies was used to determine CD3⁺ cells (whole T cells), CD19⁺ cells (B lymphocytes), CD16⁺ and CD56⁺ cells (natural killer cells), CD4⁺ cells (T-helper cells), CD8⁺ cells (T-suppressor cells), the CD4⁺/CD8⁺ (helper/supressor ratio), and Fc receptors on granulocytes. Serum was analyzed for soluble CD14 receptors (scD14), interleukin 1, interleukin 6 and prostaglandin E₂ (PGE₂). Functional stimulation assays were performed to determine the basal and induced level of reactive oxygen intermediate (ROI) production by polymorphic neutrophils. Exposure to tobacco smoke in both groups was confirmed by dosimetry of carboxyhemoglobin, plasma nicotine, and cotinine levels. In comparison to nonsmokers, smokers had elevated granulocyte cell counts, increased CD16⁺ and CD56⁺ cell levels and decreased CD3⁺ and CD19⁺ levels. Acute smoking, but not exposure to ETS, resulted in a slight decrease in the number of CD19⁺ cells and an increase in the number of granulocytes; the latter was restricted to one subject. Acute smoking and exposure to high experimental concentrations of ETS resulted in a slight increase in CD16⁺ and CD56⁺ cells. None of the changes determined in immunological parameters after either acute smoking or exposure to ETS reached statistical significance. Serum sCD14, cytokine and PGE₂, functional stimulation of in vitro ROI production, and changes in Fc receptors were not affected by acute smoking or exposure to ETS. Although no clear guidelines exist to assess immunotoxicity in man, our data do not favor immunosuppression and the possibility of increased risk of infection in nonsmokers exposed to ETS under real-life conditions.Abbreviations AM alveolar macrophage - BALF bronchoalveolar lavage fluid - CO carbon monoxide - CO₂ carbon dioxide - COHb carboxyhemoglobin - ELISA enzyme linked immunoassay - ETS environmental tobacco smoke - FITC fluorescein isothiocyanate - IL interleukin - MHC major histocompatibility complex - NK natural killer cell - NO nitrogen oxide - NO₂ nitrogen dioxide - PBS phosphate-buffered saline - PE phycoerythrin - PGE₂ prostaglandin E₂ - PMA phorbol-12-myristate-13-acetate - PMN polymorphic neutrophils - RIA radioimmunoassay - ROI reactive oxygen intermediates - RSP respirable suspended particles - sCD14 soluble CD14 receptor     

Physical mapping of the albino-deletion complex in the mouse to localize alf/hsdr-1, a locus required for neonatal survival.

The albino-deletion complex in the mouse defines a genetically well-characterized region of chromosome 7 in which a number of loci essential for normal development and viability reside. One locus, designated alf or hsdr-1, is necessary for neonatal survival. Its absence results in hypoglycemia associated with biochemical and ultrastructural abnormalities in hepatocytes and proximal tubule cells of the kidney. We constructed a long-range physical map of the region defined by the proximal segment of the albino-deletion complex as a step toward localizing alf/hsdr-1. Sixteen markers, including 11 whose isolation is described here and in the accompanying paper (A. Schedl et al., 1992, Genomics 14, 288-297), were ordered on a panel of albino-deletion DNAs and their distribution was examined by pulsed-field gel electrophoresis. The resulting approximately 4300-kb physical map covers the entire region absent from the prototypic alf/hsdr-1 deletion c14CoS, estimated as approximately 3600 kb. Since the deletion c11DSD complements and overlaps most of c14CoS, alf/hsdr-1 was mapped at the proximal extreme of c14CoS, approximately 3000 kb from the albino locus. The density of CpG islands was found to be very heterogeneous across the region mapped.