Neuromedin U-immunoreactivity in the nervous system of the small intestine of the pig and its coexistence with substance P and CGRP

Summary In the small intestine of the pig, neuromedin U (NMU)-immunoreactivity was mainly confined to the nerve plexus of the inner submucosal and mucosal regions. After colchicine treatment, a high number of immunoreactive nerve cell bodies was observed in the plexus submucosus internus (Meissner), whereas only a low number was found in the plexus submucosus externus (Schabadasch). The plexus myentericus as well as the aganglionic nerve meshworks in the circular and longitudinal smooth muscle layers almost completely lacked NMU-immunoreactivity. Double-labeling experiments demonstrated the occurrence of distinct NMU-containing neuron populations in the plexus submucosus internus: (1) relatively large type-II neurons revealing immunoreactivity for NMU and calcitonin gene-related peptide (CGRP) and/or substance P (SP); (2) a group of small NMU- and SP-immunoreactive neurons; (3) a relatively low number of small neurons displaying immunoreactivity for NMU but not for SP. Based on its distributional pattern, it is concluded that NMU plays an important role in the regulation and control of mucosal functions.     

Synthesis of phage-specific transfer RNA molecules by vibriophage phi 149

32P-Labelled tRNA was isolated from uninfected and phage phi 149-infected Vibrio cholerae cells. These tRNA preparations were then hybridised with DNA isolated from phage phi 149. Significant hybridisation was observed only with tRNA from phage phi 149-infected cells. This strongly suggests that infection of classical vibrio with phage phi 149 results in the synthesis of phage-specific tRNA molecules.     

Aminoacyl-tRNA synthetases: inter-site interaction as a possible proofreading mechanism

Smooth muscle cell energetics of taenia caeci during relaxation, activity and maximal contraction were investigated using ³¹P-NMR. In relaxed muscle obtained in calcium-free medium, [ATP], [phosphocreatine] and [sugar phosphate] were 4.4 mM, 7.7 mM and 2.8 mM, respectively. There was only a small difference in the energetics of spontaneously active and maximally contracted muscles, but under both conditions substantial changes occurred as compared with relaxed muscles. The internal pH in relaxed muscle was found to be 7.05, which acidified to 6.5 during contraction. The level of sugar phosphates was found to be not a limiting factor in energetics.     

Substance P and enkephalin in transected axons of medulla and spinal cord

The accumulation of transported materials in cut axons is demonstrated by the light and electron microscopic immunocytochemical localization of substance P and enkephalin in the caudal medulla and cervical spinal cord of adult rat. Two days following unilateral knife-cuts in the caudal medulla or spinal (C2-C3) levels, substance P and enkephalin-like immunoreactivity (SPLI and ELI) are detected in lesioned axons located rostral and caudal to the transection. Rostrally, SPLI and ELI are detected in the lateral reticular region and ventrolateral fasciculus corresponding to the location of previously identified bulbospinal pathways. Caudally, previously unidentified, propriospinal pathways showing SPLI are detected in the dorsal columns and in the dorsolateral fasciculus. In contrast, ELI is found caudal to the transection only in the reticular region of the medulla. For both peptides, immunoreactivity is present throughout axons containing numerous large, dense core, and small clear vesicles. These results support the concept of both particulate and soluble modes of transport for substance P and enkephalin within axons of the central nervous system.     

Ligation of highly modified bacteriophage DNA

After digestion by TaqI or nicking by DNAase I, five highly modified bacteriophage DNAs were tested as substrates for T4 DNA ligase. The DNAs used were from phages T4, XP12, PBS1, SP82, and SP15, which contain as a major base either glucosylated 5-hydroxymethylcytosine, 5-methylcytosine, uracil, 5-hydroxymethyluracil, or phosphoglucuronated, glucosylated 5-(4′,5′-dihydroxypentyl)uracil, respectively. The relative ability of cohesive-ended TaqI fragments of these DNAs and of normal, λ DNA to be ligated was as follows: $\text{λ}\text{DNA}\text{=}\text{XP}\text{12}\text{DNA}\text{>}\text{<font color="red">SP</font>}\text{82}\text{DNA}\text{?}\text{nonglucosylated}\text{T}\text{4}\text{DNA}\text{>}\text{T}\text{4}\text{DNA}\text{=}\text{PBS}\text{1}\text{DNA}\text{?}\text{<font color="red">SP</font>}\text{15}\text{DNA}$. TaqI-T4 DNA fragments were also inefficiently ligated by Escherichia coli DNA ligase. However, annealing-independent ligation of DNAase I-nicked T4, PBS1, and λ DNAs was equally efficient. We conclude that the poor ligation of TaqI fragments of T4 and PBS1 DNAs was due to the hydroxymethylation (and glucosylation) of cytosine residues at T4's cohesive ends and the substitution of uracil residues for thymine residues adjacent to PBS1's cohesive ends destabilizing the annealing of the restriction fragments. Only SP15 DNA with its negatively charged, modified base was unable to serve as a substrate for T4 DNA ligase in an annealing-independent reaction; therefore, its modification directly interfered with enzyme binding or catalysis.     

Colocalization of NADPH-diaphorase activity and certain neuropeptides in the esophagus of opossum (Didelphis virginiana)

Nitric oxide and various neuropeptides in the myenteric plexus regulate esophageal motility. We sought colocalization of nitric oxide synthase and neuropeptides in frozen sections of mid-portion of smoothmuscled opossum esophagus using NADPH-diaphorase activity to mark the synthase and immunoreactivity to detect peptides. The peptides, all with demonstrated physiological activity in this organ, were calcitonin generelated peptide, galanin, neuropeptide Y, substance P, and vasoactive intestinal polypeptide. The ExtrAvidin Peroxidase immunostain for each peptide was carried up to the final peroxidase reaction with 3-amino-9-ethylcarbazole. The NADPH-diaphorase reaction was applied with short incubation to provide light staining just before the peroxidase reaction was performed. We examined sections for the proportions of singly and dually labeled nerve cells in the myenteric plexus. NADPH-diaphorase activity was highly colocalized with calcitonin gene-related peptide (59%), galanin (54%), and vasoactive intestinal polypeptide (53%). It showed little colocalization with neuropeptide Y (10%) and substance P (8%). The proportions of all nerve cells containing each of the substances were: NADPH-diaphorase-33%, calcitonin gene-related peptide-30%, galanin-55%, neuropeptide Y-16%, substance P-35%, and vasoactive intestinal polypeptide-58%. We conclude that the nerves responsible for peristalsis in the esophagus may act by releasing nitric oxide along with other inhibitory substances, calcitonin gene-related peptide, galanin, and vasoactive intestinal polypeptide, but not excitatory substances, neuropeptide Y and substance P.     

生物素标记HBV RNA探针的制备及应用

本文首次采用ＳＰ６５特殊质粒与人类的乙型肝炎病毒ＤＮＡ重组,制备了Ｂｉｏ－ＨＢＶ ＲＮＡ探针,能特异地与ＨＢＶ ＤＮＡ杂交,将该探针与缺口转移方法标记的Ｂｉｏ－ＨＢＶ ＤＮＡ探针进行了比较,结果显示出Ｂｉｏ－ＨＢＶ ＲＮＡ探针比Ｂｉｏ－ＨＢＶ ＤＮＡ探针的敏感性提高１０倍,并分别应用两种探针同时检测７０例乙肝病人血清中ＨＢＶ ＤＮＡ,阳性率各为３１．４２％、２８．５７％（Ｐ＞０．２５）。对Ｂｉｏ－     

Helospectin-like immunoreactivity in the esophagus

Helospectin I and II are two non-amidated, VIP-like peptides, isolated from the salivary gland venom of the lizard Heloderma horridum. The lower esophagus of cat, sheep and man was analyzed for helospectin-like immunoreactivity.

Immunocytochemistry revealed helospectin-immunoreactive nerve fibers in the muscle layers, submucosa and mucosa of all species studied. In myenteric ganglia helospectin-immunoreactive nerve fibers and nerve cell bodies could be seen. Double immunostaining for helospectin and vasoactive intestinal peptide (VIP) revealed their coexistence in nerve fibers and cell bodies throughout the lower esophagus of all species tested. Double immunostaining for helospectin and neuropeptide Y revealed their coexistence in nerve fibres surrounding vascular and non-vascular smooth muscle. In the cat and sheep (but not in man) a subpopulation of the helospectin/VIP-containing fibers stored, in addition, substance P.

The helospectin-immunoreactive material in the esophagus probably constitutes a novel neuropeptide. The distribution of the VIP/helospectin-immunoreactive neurons and fibers indicates their possible involvement in the regulation of motor and secretory activities.     

Isolation of Four Isomers of the 20,000 Dalton Variant of Human Pituitary Growth Hormone

A simple procedure has been developed which for the first time describes the isolation of isomers of the 20, 000 dalton variant of human growth hormone (20K hGH). From a human pituitary hormone concentrate different hGH dimers (covalently and noncova-lently linked) were enriched by chromatography on SP-Sephadex C-50, DEAE-Sepharose CL-6B and Sephadex G-100. Noncovalently-1inked dimers were split by 6 M urea into 20K hGH and 22K hGH monomers. A complete group-separation of 20K hGH and 22K hGH monomers was achieved by chromatography on DEAE-Sepharose CL-6B at neutral pH. The 20K hGH monomer was resolved into four isomers either by preparative isoelectric focusing or by zone electrophoresis in agarose suspension at alkaline pH. The three latter techniques were all used in the presence of 6 M urea. Radioimmunoassay and radioreceptorassay indicated that the isomers obtained were true components of human growth hormone.