B1 and B2 Bradykinin Receptors Encoded by Distinct mRNAs

Abstract: Bradykinin receptors have been subdivided into at least two major pharmacological subtypes, B₁ and B₂. The cDNAs encoding functional B₂ receptors have recently been cloned, but no molecular information exists at present on the B₁ receptor. In this article, we describe experiments examining the possible relationship between the mRNAs encoding the B₁ and B₂ types of receptor. We showed previously that the Human fibroblast cell line W138 expresses both B₁ and B₂ receptors. In this report, we describe oocyte expression experiments showing that the B₁ receptor in W138 human fibroblast cells is encoded by a distinct mRNA ∼2 kb shorter than that encoding the B₂ receptor. We have used an antisense approach in conjunction with the oocyte expression system to demonstrate that the two messages differ in sequence at several locations throughout the length of the B₂ sequence. Taken together with the mixed pharmacology exhibited in some expression systems by the cloned mouse receptor, the data indicate that B₁-type pharmacology may arise from two independent molecular mechanisms.     

Relation between infection with Helicobacter pylori and living conditions in childhood: evidence for person to person transmission in early life.

OBJECTIVES--To relate the prevalence of infection with Helicobacter pylori in adults to their living conditions in childhood to identify risk factors for infection. DESIGN--Prevalence study of IgG antibodies to H pylori (> 10 micrograms IgG/ml, determined by enzyme linked immunosorbent assay (ELISA)) and reported living conditions and other socioeconomic factors in childhood. SETTING--Three factories in Stoke on Trent. SUBJECTS--471 male volunteers aged 18 to 65 years. MAIN OUTCOME MEASURES--Seroprevalence and variables in childhood. RESULTS--Seroprevalence of H pylori increased with age (22/74 (29.7%) at < 30 years v 29/46 (63%) at 55-65 years; P < 0.001 for trend) and was related to manual occupation (14/65 (21.5%) for non-manual v 162/406 (39.9%) for manual; P = 0.003). After data were adjusted for age and occupation subjects from large families, whose childhood homes were crowded or who regularly shared a bed in childhood, were significantly more likely to be seropositive (adjusted odds ratio (95% confidence interval) 2.15 (1.41 to 3.30) for crowding and 2.13 (1.38 to 3.30) for sharing a bed), but there was no relation with possession of a bathroom, inside toilet, refrigerator, or household pets in childhood. CONCLUSIONS--Close person to person contact in childhood is an important determinant of seroprevalence of H pylori in adulthood, suggesting that the infection is transmitted directly from one person to another and may be commonly acquired in early life.     

Purification of allantoinase from soybean seeds and production and characterization of anti-allantoinase antibodies.

Allantoinase catalyzes the hydrolysis of allantoin to allantoic acid, a reaction important in both biogenesis and degradation of ureides. Ureide production in cotyledons of germinating soybean (Glycine max L.) seeds has not been studied extensively but may be important in mobilizing nitrogen reserves. Allantoinase was purified approximately 2500-fold from a crude extract of soybean seeds by differential centrifugation, heat treatment, ammonium sulfate fractionation, ethanol fractionation, and fast protein liquid chromatography (Pharmacia) with Mono-Q and Superose columns. The purified enzyme had a subunit size of 30 kD. Polyclonal antibodies produced against the purified protein titrated allantoinase activity in a crude extract of seed proteins. Antibodies recognized the 30-kD band in western blot analysis of crude seed extracts, indicating that they were specific for allantoinase.     

Biology and life cycle ofAtelocauda koae,an unusual demicyclic rust

Atelocauda koae, a rust of the native HawaiianAcacia koa, is considered as a demicyclic species, having spermogonial, aecial, and telial states, but is unusual in production of aeciospores simultaneously with teliospores rather than consecutively. Host inoculation with spores of each state separately confirmed that the life cycle was perpetuated by the telial state, but the aeciospores, while capable of germination and stomal penetration, did not produce detectable infection. This rust therefore behaves as a microcyclic species, and appears to be in evolutionary transition toward this reduced state. Teliospores produced vestigial, permanently attached basidiosopores which germinated to produce infective hyphae. The hyphae entered the host either through stomata or penetrated the epidermis directly, with the latter method being more common. Unusual nuclear associated with teliospore germination, in which meiosis occurs in more than one diploid nucleus was observed, in confirmation of an earlier study.     

Molecular dynamics of alamethicin transmembrane channels from open-channel current noise analysis.

Conductance noise measurement of the open states of alamethicin transmembrane channels reveals excess noise attributable to cooperative low-frequency molecular dynamics that can generate fluctuations approximately 1 A rms in the effective channel pore radius. Single-channel currents through both persistent and nonpersistent channels with multiple conductance states formed by purified polypeptide alamethicin in artificial phospholipid bilayers isolated onto micropipettes with gigaohm seals were recorded using a voltage-clamp technique with low background noise (rms noise < 3 pA up to 20 kHz). Current noise power spectra between 100 Hz and 20 kHz of each open channel state showed little frequency dependence. Noise from undetected conductance state transitions was insignificant. Johnson and shot noises were evaluated. Current noise caused by electrolyte concentration fluctuation via diffusion was isolated by its dependence on buffer concentration. After removing these contributions, significant current noise remains in all persistent channel states and increases in higher conductance states. In nonpersistent channels, remaining noise occurs primarily in the lowest two states. These fluctuations of channel conductance are attributed to thermal oscillations of the channel molecular conformation and are modeled as a Langevin translational oscillation of alamethicin molecules moving radially from the channel pore, damped mostly by lipid bilayer viscosity.     

Increased yields of Rhizobium japonicum by an extract of the green alga,Scenedesmus obliquus (276-3a)

Summary The effects of algal extract (AE) and yeast extract (YE) on the growth of Rhizobium japonicum were studied. YE concentrations above 0,1% inhibited growth. Increased concentrations of AE in growth medium increased bacterial yield up to an extract concentration of 1%. At 1% AE concentration maximum yields were achieved which were 3 times greater than those achieved with YE.     

Relationship between the transport from isolated nuclei of two abundant cytoplasmic messengers and the source of a messenger RNA transport factor

Messenger RNA transport from isolated nuclei requires a 35×10³ dalton cytoplasmic protein(s) which is present in both the cytosol and polyribosome fractions. Recombinant DNA probes containing cDNA inserts were used to quantitate the transport of rat liver-specific albumin and male rat liver-specific ₂U-globulin messenger RNA (mRNA) from male rat liver nuclei in response to the mRNA transport factors from homologous and heterologous tissues. No mRNA transport occurs in the absence of the transport factor(s). Both messengers are transported proportionately in response to the factor(s) from male or female rat liver cytosol, or from the polyribosomes (messenger ribonucleoprotein) of male or female rat liver, or brain. The transport factor(s) do not, therefore, appear to differentiate between the coding sequences of two unrelated hepatic messenger RNA's.     

Cytomat-R: a computer-controlled multiple laser source multiparameter flow cytophotometer system.

A multiple illumination wavelength multiparameter flow cytophotometer system, using laser sources and controlled by a small, general-purpose digital computer, has been produced for use in the development of new flow cytometric techniques. Three different laser wave-lengths can be used simultaneously to illuminate different regions of the flow chamber; as many as five measurements of light scattering at various angles, extinction, and fluorescence at one or more wavelengths can be made at each illuminated station. Cells in suspension may be examined at rates of 1000 cells/sec, with seven correlated optical measurements being recorded for each cell. A library of programs for data manipulation and statistical analysis make it possible to use the system to develop and implement cell characterization, counting and classification procedures for basic and clinical research applications.     

Neurotubule assembly at substoichiometric nucleotide levels using a GTP regenerating system

Tubulin derived from cold depolymerized bovine microtubules has been gel filtered to obtain a tubulin preparation with only 3% of the tubulin dimers containing exchangeable [³H]-guanine nucleotide. In the presence of acetyl-P and bacterial acetate kinase, this preparation polymerizes to form microtubules which are morphologically indistinguishable from microtubules formed in the presence of excess GTP. The extent of microtubule formation at substoichiometric nucleotide levels using the GTP regenerating system exceeds the extent of assembly obtained with excess GTP. It is concluded that the exchangeable guanine nucleotide site can be virtually unoccupied in intact neurotubules and this finding indicates that GDP can “catalyze” tubule assembly in the presence of a GTP regenerating system.