The present study investigated the role of nitric oxide (NO)/cGMP signal transduction in the M 3 muscarinic acetylcholine receptor (mAChR)-stimulated increase in aquaporin-5 (AQP5) levels in the apical plasma membrane (APM) of rat parotid glands. Pretreatment of rat parotid tissue with the NO scavenger 2-(4carboxyphe-nyl)-4,4,5,5-tetramethyl-imidazoline-1-oxyl-3-oxide potassium inhibited both acetylcholine (ACh)-and pilocarpine-induced increases in AQP5 in the APM. NO donors [3-morpholinosydnonimine (SIN-1) and (S)-nitroso-N-acetylpenicillamine (SNAP)] mimicked the effects of mAChR agonists. A selective protein kinase G inhibitor [(9S,10R,12R)-2,3,9,10,11,12-hexahydro-10-methoxy-2,9-dimethyl-1-oxo-9,12-epoxy-1H-diindolo-[1,2,3-fg-3Ј,2Ј,1Ј-kl]pyrrolo [3,4-i] . These results suggest that NO/cGMP signal transduction has a crucial role in Ca 2ϩ homeostasis in the mAChR-stimulated increase in AQP5 levels in the APM of rat parotid glands.Several aquaporins (AQPs), which form water channels that selectively transport water across the plasma membrane, have been cloned from a variety of mammalian tissues (King and Agre, 1996). In the gastrointestinal tract, more than seven AQPs are known to be expressed: AQP1 in intrahepatic cholangiocytes; AQP4 in gastric parietal cells; AQP3 and AQP4 in colonic surface epithelium; AQP5 in salivary glands; AQP7 in small intestine; AQP8 in liver, pancreas, colon, and salivary glands; and AQP9 in liver (Ma and Verkman, 1999). AQP5 was cloned from the rat submandibular gland (Raina et al., 1995). The nucleotide sequence of AQP5 reveals 45 and 63% homology with AQP1 and AQP2, respectively (Raina et al., 1995). Salivary fluid secretion is defective in transgenic mice lacking AQP5, indicating that AQP5 is important in salivary gland function Krane et al., 2001). The sympathetic and parasympathetic nerves in rat parotid glands regulate the role of AQP5. Acetylcholine (ACh) and epinephrine acting at M 3 muscarinic acetylcholine receptors (mAChR) and ␣ 1 -adrenoceptors, respectively, inThis work was supported in part by a grant-in-aid for scientific research from the Ministry of Education, Culture, Sports, Science, and Technology of Japan.ABBREVIATIONS: AQP, aquaporin; ACh, acetylcholine; mAChR, muscarinic acetylcholine receptor; APM, apical plasma membrane; SNI-2011, cevimeline hydrochloride; PLC, phospholipase C; IP 3, inositol 1,4,5-trisphosphate; DAG, 1,2-diacylglycerol; PKC, protein kinase C; CaM, calmodulin; MLCK, myosin light chain kinase; NOS, nitric-oxide synthase; GC, guanylate cyclase; NO, nitric oxide; PKG, protein kinase G; BAPTA-AM, 1,2-bis(2-aminophenoxy)ethane-N,N,NЈ,NЈ-tetraacetic acid-acetoxymethyl ester; Carboxy-PTIO, 2-(4carboxyphenyl)-4,4,5,5-tetramethyl-imidazoline-1-oxyl-3-oxide potassium; IBMX, 3-isobutyl-1-methylxanthine; SIN-1, 3-morpholinosydnonimine; SNAP, (S)-nitroso-N-acetylpenicillamine; KN-62; (8)-5-isoquinolinesulfonic acid, 4-[2-(5-isoquinolinyl-sulfonyl)methylamino]-3-oxo-(4-phenyl-1-piperazinyl)-propyl]phenyl ester; ML9, (5-chloronaphthalene-1-sulfonyl...

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Three conjugates of imidazole (Im)-pyrrole (Py) diamide and a DNA-alkylating moiety derived from the antibiotic duocarmycin A were synthesized, and their sequence specificity, reactivity, and antitumor activity comparatively examined. Sequencing gel analysis indicated that ImPyDu (1) alkylates DNA at the 3' end of AT-rich sequences at micromolar concentration. ImPyDu86 (2) reacts with DNA at AT-rich sites together with dialkylation sites at micromolar concentration. ImPyLDu86 (3) efficiently alkylates dialkylation sites at nanomolar concentration. Average values of log IC(50) against a 39 cancer cell line panel of 1-3 were -4.59, -5.95, and -8.25, respectively. The differential growth inhibition pattern of 1-3 varied with relatively low correlation coefficients. Array-based gene expression monitoring was performed for 3 in a human lung cancer cell line. Substantial downregulation of expression was seen for genes involved in DNA damage response, transcription, and signal transduction.

Nonylphenol (NP) is an important intermediate in the production of various commercial and industrial materials, but is also known as a ubiquitous pollutant in urban aquatic environments. We recently studied the NP-degrading activities of microflora in several aquatic environments, and found a notable degrading activity for wastewater from a sewage treatment plant in Tokyo. This result led us to isolate NP-degrading microbes and identify biodegradation products. Using conventional plate culture techniques and molecular biological methods, Pseudomonas and Sphingomonas species, which are known for their degradation activities of many aromatic compounds, have been isolated. But it has also been found that Sphingomonas sp. (S-strain) is necessary and sufficient for the degradation of NP. Although the role of Pseudomonas sp. (P-strain) remains unclear, P-strain seems to provide some co-nutrients for the growth of S-strain. The degradation products were analyzed by GC/MS and NMR. More than 95% of NP was degraded within 10 days and aromatic compounds other than NP were not found, suggesting that the phenolic part of NP was completely degraded. We also examined the potential of S-strain for bioremedial applications. S-strain cells immobilized on chitosan or alginate beads retain their NP-degrading activity in flask-scale experiments. Furthermore, the chitosan-bound cells in a lab-scale bioreactor have been found to be persistent for repeated use, suggesting that S-strain is applicable to the treatment of NP-contaminated wastewater.