Similarity between 5'- and 3'-terminal nucleotide sequences and double-stranded RNA-derived sequences of eukaryotic mRNA

It has been reported recently that parts of the nucleotide sequences present in the 5′- and 3′-terminal regions of cytoplasmic mRNA are derived from double-stranded hairpin structures of heterogeneous nuclear RNA—a putative mRNA precursor (Naora, 1979). In order to explore the nature of double-stranded hairpin structures, using the sequencing data of human and rabbit globin mRNA and hen ovalbumin mRNA, we examined the following possibility: that certain regions of both the 5′- and 3′-terminal nucleotide sequences of mature mRNA were present in double-stranded hairpin structures covalently linked to both sides of the message sequence in the precursor mRNA molecule and that these double-stranded hairpin structures are similar to each other. The results support the above possibility by showing substantial similarity of nucleotide sequences between the 5′- and 3′-terminal regions of these mRNAs in terms of the formation of similar double-stranded hairpin structures.     

Effect of serum,fibronectin, and laminin on adhesion of rabbit intestinal epithelial cells in culture

Rabbit intestinal epithelial cells, obtained after a limited hyaluronidase digestion, were incubated in medium with or without calf serum, on bacteriological plastic dishes. The dishes, either plain or coated with an air-dried type I collagen film, were pretreated with medium alone or with medium containing purified laminin or purified fibronectin. Cells did not attach in significant numbers to untreated bacteriological plastic, even in the presence of serum. Cells did attach to collagen-coated dishes, and were judged viable on the basis of their incorporation of radiolabeled leucine into cell protein. Cell adhesion to the collagen substrate increased in proportion to the concentration of serum in the medium, with maximal attachment at 5% serum or greater. Pretreatment of plain or collagen-coated dishes with increasing amounts of fibronectin enhanced cell adhesion in a concentration-dependent manner. Either serum, or fibronectin-free serum in the medium enhanced cell attachment to substrates pretreated with cither fibronectin or laminin. Thus, intestinal epithelial cells appear to possess surface receptors for both laminin and fibronectin. The evidence further suggests that calf serum may contain factors, other than fibronectin, capable of enhancing intestinal epithelial cell attachment to collagen substrates.     

Effects of guanine nucleotides on cns neuropeptide receptors

The effect of nucleotides on central nervous system neuropeptide receptor binding was investigated. The guanine nucleotides, guanosine-5′-triphosphate and guanylyl-5′-imidodiphosphate, significantly inhibited the binding of radiolabeled vasoactive intestinal polypeptide but not that of [Tyr⁴]bombesin to rat brain membranes. Vasoactive intestinal polypeptide binding was inhibited by guanine nucleotides in a dose-dependent manner. Using a 20 μM dose, 60% of the specific vasoactive intestinal polypeptide binding was inhibited by guanylyl-5′-imidodiphosphate, which was more potent than guanosine-5′-triphosphate, whereas other nucleotides were not effective. This reduction in binding was a consequence of lower affinity of the receptor for vasoactive intestinal polypeptide, which in turn resulted from an increased rate of dissociation.     

13C nmr studies of aurothioglucose: Ligand exchange and redox disproportionation reactions

¹³C nmr studies of gold thioglucose, AuSTg, and solutions containing added β-1-D-thioglucose, TgSH, have been conducted at PD 7.4 and interpreted in terms of complexation and ligand exchange reactions that are consistent with the known preference of gold(I) for linear two-coordinate structures. The upper limit of the half-life for ligand exchange between 0.25 M Au(STg)₂^? and TgSH at pD 7.4 is 2.2 msec. The ¹³C nmr spectra of various thioglucose derivatives have been assigned. A novel oxidation reduction reaction was discovered that leads to the formation of metallic gold and a product tentatively identified as the sulfinic acid derivative of thioglucose. The presence of sulfinic acid in AuSTg was indicated by the infrared absorption at 1050 cm^?1. The same product was formed by slow hydrolysis of thioglucose disulfide. A mechanism for the formation of the sulfinic acid derivative from AuSTg is proposed.     

Role of the duodenum in motilin release

In order to study the regulatory mechanism of motilin release, plasma motilin was measured in healthy dogs during the fasting state and after the ingestion of ordinary nutrient. Fasting plasma motilin levels were found to fluctuate intermittently, but ingestion of a meal completely abolished the intermittent motilin release and resulted in low motilin levels lasting for 6–8 h. To clarify the role of the duodenum in this motilin release, an operation was performed in five dogs by which we excluded from the alimentary tract the upper half of the small intestine not including the duodenum from a point 2 cm below the larger pancreatic duct. After this operation meal ingestion still caused a decrease in plasma motilin levels. However, after a modified version of the operation was performed in 5 other dogs by which the upper half of the small intestine together with the duodenum was transected at the pyloric ring, plasma motilin was not suppressed by meal ingestion. These results suggest that motilin secretion is regulated by nutrient ingestion and that the passage of nutrients through the duodenum plays a important role in its regulation.     

Pharmacological comparison of bPTH-(1–34) and other hypotensive peptides in the dog

The purpose of the present study was to compare the potency, effectiveness and duration of action of synthetic bPTH-(1–34) with those of other known hypotensive peptides in the anesthetized dog. Of sixteen peptides tested in the present study only 8 were demonstrated to possess hypotensive activity. While bPTH-(1–34) was one of the least potent of the hypotensive peptides, it was equal to or greater than the other peptides in terms of effectiveness and duration of action. Of all the peptides studied, substance P and eledoisin were the most potent in terms of their hypotensive action. It is suggested that perhaps substance P and eledoisin might act at a different site or through different mechanisms than do vasoactive intestinal peptide (V.I.P.), corticotropin inhibiting peptide (C.I.P.), neurotensin, xenopsin, bradykinin and bPTH-(1–34).     

Systemic injections of gastro-intestinal peptides alter behavior in rats

Twenty-four male albino rats were given daily intraperitoneal injections of vasoactive intestinal polypeptide (VIP), motilin, human gastrin I (1–17) or the diluent control vehicle at a dose of 100 μg/kg for four consecutive days and food intake, water intake, body weight, and running wheel activity were determined every 24 hours. Animals injected with motilin or human gastrin I (1–17) exhibited decreased food intake relative to those injected with VIP or diluent, which did not differ from each other, although food intake increased reliably over days. The mean water consumption followed the same pattern as that of food intake. As expected from the above results, VIP produced weight gains as compared with rats injected with motilin or gastrin but not reliably more than after diluent. A reliable effect of trials for weight gain was the greatest on day three. Running wheel activity was not affected by injections of human gastrin I (1–17), motilin, or diluent but was reliably decreased by VIP. No significant differences existed across days. Although the results indicate that GI peptides may affect behavior when injected systemically and that like other peptides they have multiple effects, caution is urged in the interpretation of behavioral results at this time.     

A retinal projection to the lateral hypothalamus in the rat

Summary This study presents evidence for a retinal projection to neurons in the lateral hypothalamic area (LHA) of the albino rat. In Golgi-Kopsch material dendrites from LHA-neurons are observed to extend through the supraoptic commissures into the optic tract. The presence of dendrites in the optic tract is confirmed by electron microscopy. Numerous axon terminals are observed forming asymmetric synaptic contacts with these dendritic profiles. Following bilateral enucleation, many of the preterminal axons and terminals in synaptic contact with dendrites in the optic tract demonstrate dark degeneration. After intraocular injection of horseradish peroxidase, there is marked labeling of preterminal axons and terminals in the optic tract. These observations indicate that LHA neurons receive a direct retinal projection from terminals making synaptic contact with dendrites of LHA-neurons extending into the optic tract.     

Nerves containing substance P,vasoactive intestinal polypeptide,enkephalin or somatostatin in the guinea-pig taenia coli

Summary The guinea-pig taenia coli is rich in peptide-containing nerves. Nerve fibres containing substance P (SP), vasoactive intestinal peptide (VIP), or enkephalin, were numerous in the smooth muscle while somatostatin fibres were very few. Nerve fibres displaying SP or VIP immunoreactivity were numerous in the myenteric plexus. Enkephalin nerve fibres were fairly numerous in the plexus while somatostatin nerve fibres were sparse. Nerve cell bodies containing immunoreactive SP or VIP were regularly seen in the plexus. Delicate varicose elements of the different types of nerve fibres were found to ramify around nerve cell bodies in a manner suggestive of innervation.In the electron microscope the various peptide-storing nerve fibres (i.e., elements containing SP, VIP or enkephalin) were found to contain a varying number of fairly large, electron-opaque vesicles in the varicose swellings. These vesicles represent the storage site of the neuropeptides.The isolated taenia coli responded to electrical nerve stimulation with a contraction. After cholinergic and adrenergic blockade the contractile response was replaced by a relaxation followed by a contraction upon cessation of stimulation. SP contracted the taenia while VIP caused a relaxation. The enkephalins raised the resting tension slightly while somatostatin had no effect. These observations are compatible with a role for SP as an excitatory neurotransmitter and for VIP as an inhibitory one, and with the view that both SP neurones and VIP neurones act as motor neurones. In preparations contracted by SP the electrically induced contractions were reduced in amplitude while the electrically induced relaxations seen after adrenergic and cholinergic blockade were enhanced in amplitude. In preparations relaxed by VIP there was an increased contractile response to electrical stimulation, while in the atropine + guanethidine-treated preparation the electrically induce relaxations were reduced in amplitude. The enkephalins reduced the contractile response to electrical stimulation, while somatostatin induced a very small reduction in the amplitude of such responses. These observations suggest that SP neurones and VIP neurones may play additional roles as interneurones. Somatostatin neurones probably act as interneurones. Enkephalin-containing fibres may serve to modify the release of transmitter from other nerves in the smooth muscle, perhaps through axo-axonal arrangements. Alternatively, the enkephalin nerve fibres in the smooth muscle are afferent elements involved in mediating sensory impulses to the myenteric plexus.     

Lymphokines in sensitized rats. III. Influence of prednisolone treatment of lymph node and spleen architecture in sensitized rats and upon MIF release in vitro.

The influence of prednisolone (corticosteroid, C.S.) treatment upon established cell-mediated immunity (CMI) induced by complete Freund's adjuvant (CFA) has been studied in rats by using in vitro migration inhibitory factor (MIF) assays, type IV skin reactions, and regional lymph node and spleen histology. Additionally, changes in the mononuclear-polymorphonuclear ratio of peripheral blood and T-cell accumulation in bone marrow in response to C.S. treatment have been determined. These results have been evaluated by comparison with equivalent experiments upon animals treated with anti-rat lymphocyte serum (ALS), oxisuran, or 2-[(methylsulfinyl)-acetyl]pyridine, which selectively suppresses CMI. The results suggest the existence of a population of “educated” T-cells in the thymic cortex of sensitized rats, and they suggest that prolonged C.S. administration does not suppress T-effector cells involved in established CMI but, rather, affects lymphocyte and monocyte migration patterns, including the migration of educated T-cells from the thymic cortex into other tissue compartments.