Implications for cytoplasmic pH,protonmotice force,and amino-acid transport across the plasmalemma of Riccia fluitans

By means of pH-sensitive microelectrodes, cytoplasmic pH has been monitored continuously during amino-acid transport across the plasmalemma of Riccia fluitans rhizoid cells under various experimental conditions. (i) Contrary to the general assumption that import of amino acids (or hexoses) together with protons should lead to cytoplasmic acidification, an alkalinization of 0.1–0.3 pH_c units was found for all amino acids tested. Similar alkalinizations were recorded in the presence of hexoses and methylamine. No alkalinization occurred when the substrates were added in the depolarized state or in the presence of cyanide, where the electrogenic H⁺-pump is inhibited. (ii) After acidification of the cytoplasm by means of various concentrations of acetic acid, amino-acid transport is massively altered, although the protonmotive force remained essentially constant. It is suggested that H⁺-cotransport is energetically interconnected with the proton-export pump which is stimulated by the amino-acid-induced depolarization, thus causing proton depletion of the cytoplasm. It is concluded that, in order to investigate H⁺-dependent cotransport processes, the cytoplasmic pH must be measured and be under continuous experimental control; secondly, neither pH nor the protonmotive force across a membrane are reliable quantities for analysing a proton-dependent process.Abbreviations 3-OMG 3-oxymethylglucose - pH_c cytoplasmic pH - _m electrical potential difference across the respective membrane, i.e. membrane potential - _H+/F (=pmf) electrochemical proton gradient     

Hepatocellular Carcinoma in Hepatitis B Surface Antigen Carriers in Eight Institutions

We reviewed records of all persons dying between 1979 and 1986 in eight California institutions for the mentally retarded. Autopsies had been done in 71% of the 1,181 deaths. Nine deaths were due to hepatocellular carcinoma, which invariably developed in carriers of hepatitis B surface antigen (HBsAg) and was fatal within four months of diagnosis. The mean age at death was 32.7 years. The incidence of hepatocellular carcinoma in HBsAg carriers was 140 times greater than in the US population. Persistent hepatitis B infection was probably etiologically related to hepatocellular carcinoma in this population, which is relatively free of exposure to other hepatocarcinogens.     

Effect of luteinizing hormone releasing hormone (LHRH) and [D-Trp6, des-Gly-NH2(10)]LHRH ethylamide on alpha-subunit and LH beta messenger ribonucleic acid levels in rat anterior pituitary cells in culture

The effect of incubation with LHRH and its agonist [D-Trp6, des-Gly-NH2(10)]LHRH ethylamide has been measured on the concentrations of mRNAs for the common alpha-subunit of glycoprotein hormones and beta-LH in rat anterior pituitary cells in primary culture. After incubation, total RNA was analyzed by Northern blot or dot blot hybridization with alpha- and LH beta 32P-labeled cRNA probes and mRNA levels were quantified by autoradiography. Short-term treatment (4-6 h) of pituitary cells with 100 nM LHRH led to a marked stimulation of LH release but no effect was observed on alpha-subunit or LH beta mRNA levels. Longer (24-72 h) incubation periods with LHRH led to complete desensitization of the LH response to the neurohormone and induced 2- to 3-fold increases in alpha-mRNA cell content while LH beta mRNA levels remained unchanged. Maximal induction of alpha mRNA accumulation was observed with an LHRH concentration as low as 0.1 nM. Incubation with the LHRH agonist [D-Trp6, des-Gly-NH2(10)]LHRH ethylamide for 24-72 h also increased alpha mRNA but did not modify LH-beta mRNA levels. It is concluded that long-term exposure of anterior pituitary cells to LHRH or to an LHRH agonist positively regulates alpha-subunit gene expression in the absence of change in LH beta mRNA levels. This observation can provide an explanation for the high plasma levels of free alpha-subunits found in patients treated chronically with LHRH agonists.     

Partition coefficients of plant cuticles for monoterpenes

Summary Cuticle/water partition coefficients (K_c/w) for d-limonene, -pinene and -pinene were determined by an extrapolation and a desorption method. The sorption experiments were carried out with isolated angiosperm and gymnosperm cuticles and with [¹⁴C]-labelled monoterpenes, which were obtained biosynthetically. Both methods were suitable for the determination of the K_c/w of volatile hydrophobic compounds. For the angiosperm cuticles the partition coefficients are of the order of 10⁴, which indicates a high accumulation of monoterpenes in the cuticle. The values of the conifer cuticles of Picea abies (L.) Karst. and Abies alba Mill., however, are lower due to their high lignin content. This is proved by the increase of the partition coefficients after removal of polar and phenolic components. The K_c/w can be estimated with good accuracy from the octanol/water partition coefficient, which was determined experimentally.     

Detection of sugar-binding proteins in membrane-depleted nuclei

Nuclear sugar-binding proteins were detected in membrane-depleted nuclei isolated from hamster BHK cells and mouse L 1210 leukemia cells by means of fluorescein-labelled neoglycoproteins. In fluorescence microscopy, the fluorescence was seen throughout the nucleus but was generally brighter over the nucleoli than over the rest of the nucleus. Flow cytofluorometry analysis demonstrated the presence of nuclear sugar-binding proteins for synthetic glycoproteins associated with different sugar residues. Among the nine neoglycoproteins used, four neoglycoproteins (namely alpha-rhamnosylated, alpha-glucosylated, N-acetyl-beta-glucosaminylated and alpha-mannosylated-6P-serum albumin) strongly labelled nuclei. Various controls strongly argue for the specificity of the nuclear labelling. The possibility that some of the sugar-binding proteins might correspond to endogenous nuclear lectins is considered.     

Structural aspects of intranuclear matrix disintegration upon RNase digestion of HeLa cell nuclei

The organization of the intranuclear elements observed in histone-depleted (2 M NaCl-extracted) HeLa cell nuclei was investigated by means of electron microscopy and two-dimensional gel electrophoresis. This work was mainly aimed at verifying whether or not an intranuclear skeleton or matrix existed, which could explain the stable attachment of RNA to the residual nuclear structure after high-salt extraction, and its three-dimensional organization. We compared the ultrastructure and the polypeptide composition of RNA-containing and RNA-depleted (RNase-treated) nuclear residues, and we visualized intermediate stages of RNase action on the intranuclear material. We showed that this material was made of two types (fibrillar and granular) of salt-resistant RNP components equally sensitive to RNase when the enzyme was used prior to high-salt extraction. At least in our material and under our experimental conditions, no intranuclear matrix could be distinguished from the residual RNP material. Our results further suggest that formation of such a matrix is a path-dependent phenomenon.     

Chemical structure of the lipid A component of Plesiomonas shigelloides and its taxonomical significance

Abstract The chemical structure of the lipid A moiety of the lipopolysaccharide of the type strain of Plesiomonas shigelloides was elucidated. It consists of a β-(1 → 6)-linked glucosamine disaccharide carrying phosphate groups at C-1 of the reducing and at C-4' of the non-reducing glucosamine. It contains a total of 6 residues of fatty acids, 2 amide-linked and 4 ester-linked. The amino groups of the backbone disaccharide are N -acylated by substituted 3-hydroxyacyl residues: at the reducing glucosamine by 3-O-(14:0)14:0; and at the non-reducing glucosamine by 3-O-(12:0)14:0.
Two residues of 3-hydroxytetradecanoic acid are linked to C-3 and C-3' of the glucosamine residues; the hydroxy groups of these ester-linked 3-hydroxytetradecanoic acids are unsubstituted. In free lipid A, the hydroxyl groups at C-4 and C-6' are unsubstituted, indicating that the 2-keto-3-deoxyoctonic acid (KDO) is linked to C-6' of the non-reducing glucosamine, as was shown with enterobacterial lipid A. The taxonomical significance of these structural details is discussed.     

Die auswirkungen der körpergrösse von Aphelinus semiflavus howard (HYM., Aphelinidae) auf einige Organe und ihre leistungsfähigkeit

Zusammenfassung Die Körpergröße von Aphelinus semillavus How. variiert in Abhängigkeit von Große und Qualität des Wirtes. Tiere aus dem gesamten Variationsbereich wurden auf größenabhängige Proportionsverschiebungen untersucht.Relative Länge und Breite des Kopfes (bezogen auf die Körperlange) nehmen mit zunehmender Körperlange ab. Die relative Lange des Abdomens wächst etwa um den gleichen Betrag:Es besteht eine negative Korrelation zwischen der relativen Länge des letzten Fühlergliedes, des Trägers wichtiger Sinnesorgane, und der Körperlange. Seine Oberfläche steht in einem etwa konstanten Verhältnis zur Körperlänge. Die Anzahl der Porenplatten nimmt mit der Körperlänge nur wenig, ihre Länge deutlicher zu.Im Komplexauge wächst die Anzahl der Ommatidien etwa proportional zur Korperlange, während seine gesamte Fläche zwar linear, aber ïiberproportional ansteigt, was durch zunehmende Große der einzelnen Facetten erreicht wird.Die Länge der Vorderfliigel ist bei Männchen und Weibchen von mehr als 1 mm Länge etwa der Körperlange proportional. Unterhalb 1 mm nimmt die relative Flügellänge mit der Körperlange ab, bis die Flügel nur noch funktionslose Rudimente bilden. Die Relation Flügel-fläche:Körpergewicht ist bei mittelgroßen Tieren am günstigsten.Jedes Ovar hat stets drei Ovariolen, unabhängig von der Körperlänge. Große Weibchen legen nur etwas größere, aber bedeutend mehr Eier als kleine. Die Anzahl der (am 7.–10. Lebenstag) täglich abgelegten Eier steigt etwa linear mit dem Logarithmus des Körpergewichts an.Die Eiablage wird während des ganzen Lebens (im Labor etwa 40 Tage) fortgesetzt, ist aber zum. Ende hin etwas geringer. Relativ zum Körper-gewicht produzieren mittelgroße Weibchen die größte Eimasse. Die Anzahl der zum Nahrungsgewinn ausgesaugten Läuse steigt mit dem Körpergewicht.Zwischen der relativen Länge des Legestachels und der Körperlange besteht eine fast lineare negative Korrelation.Die gröBenabhangigen Proportionsverschiebungen werden als Auswirkungen unterschiedlicher Wachstumstendenzen der einzelnen Organe gedeutet, die ihrerseits genetisch fixiert sind und den biologischen Sinn haben, die Lebensf ähigkeit modifikatorisch kleiner Exemplare zu sichern und damit die Ausnutzung entsprechend kleiner Wirte zu ermöglichen.Die Bedeutung der Proportionsverschiebungen für die Leistung der ganzen Population wird diskutiert. Sic ist abhängig von der Häufigkeits-verteilung der verschiedenen Körpergrößen und these wiederum von der Art-Zusammensetzung und Ernährung der Wirtsfauna.

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Summary The body size of Aphelinus semiflavus How. varies with the size and the quality of the hosts. Specimens from the whole range of variation were investigated for differences between organ proportions, which depended on size.The relative length and width of the head (based on the body length) are reduced with increasing body length. The relative length of the abdomen increases approximately by the same amount.There is a negative correlation between the relative length of the last joint of the antennae and the body length. Its surface shows a nearly constant proportion to the body length. The length of the pore plates increases with the body length more distinctly than their numbers.Within the compound eye, the number of ommatidia increases almost proportionally to the body length; the whole area of the eye increases more than proportionally because the size of the single facets also becomes greater.When the body length is greater than 1 mm, the length of the forewings is nearly proportional to the body length. At less than 1 mm, the relative length of the fore-wings is reduced with declining body length until, finally, only rudiments without any function remain. The ratio between wing area and body weight is most favourable at medium body size.Three ovarioles, independent of the body size, are present in each ovary. Big females produce considerably more eggs than small ones. The size of their eggs is only slightly enlarged. The daily egg production (at the 7^th–10^th day of life) increases nearly linearly with the logarithm of body weight. Oviposition is continued throughout the life-time of the insect (ca. 40 days in the laboratory) but it is somewhat reduced at the end. Relative to their body weight, females of medium size produce the biggest egg masses. The number of aphids utilized by the parasite for nourishment increases with the body weight of the female.A negative correlation exists between the relative length of the extended ovipositor and the body length.The proportion differences of the organs, dependent on size, are interpreted to be consequences of different growth tendencies which are genetically fixed. Apparently, the biological role of such different growth tendencies is to ensure the viability of phenotypically small specimens and in this way to make the utilisation of small hosts possible.The importance of the differences of body proportions for the effect of the whole population is discussed. It depends on the frequency distribution of the different body lengths which itself is the consequence of the composition of host species and the nutriation of the hosts.

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Herrn Prof. Dr. Hans Braun, emer. Direktor des Instituts für Pfanzenkrankheiten an der Universität Bonn, zu seinem 70. Geburts'ag am 2. Februar 1966 gewidmet.