Isolation of cDNA clones for fourteen nuclear-encoded thylakoid membrane proteins

Summary Spinach cDNA libraries, made from polyadenylated seedling RNA, have been constructed in pBR322 and the expression vector gt11. Recombinant plasmids or phage for 14 intrinsic and peripheral thylakoid membrane proteins and one stromal protein have been identified. They encode components containing antigenic determinants against the lysine-rich 34 kd, the 23 kd and 16 kd proteins all associated with the water-splitting apparatus of the photosystem II reaction center, the ATP synthase subunits gamma, delta and CF_o-II, the Rieske Fe/S protein of the cytochrome b/f complex, subunits 2, 3, 5 and 6 of the photosystem I reaction center, plastocyanin, ferredoxin oxidoreductase, chlorophyll a/b-binding apoproteins of the lightharvesting complex associated with photosystem II, and the small subunit of the stromal enzyme ribulose bisphosphate corboxylase/oxygenase. The cDNA inserts lack complementarity to plastid DNA but hybridize to restricted nuclear DNA as well as to discrete poly A⁺-mRNA species. The precursor products obtained after translation of hybrid selected RNA fractions in a wheat germ assay are imported and processed by isolated unbroken spinach chloroplasts. The imported components comigrate with the respective authentic proteins.     

Serological properties and processing in Escherichia coli K12 of OmpV fusion proteins of Vibrio cholerae

Summary Fusion proteins comprising the amino-terminal 99 amino acids of the bacteriophage MS2 replicase and various portions of OmpV a major outer membrane protein of Vibrio cholerae were expressed in Escherichia coli K12. These fusions were expressed under the control of the P_L promoter of bacteriophage , and expression was controlled using a cI_ts repressor. Fusions occurring within the secretory signal sequence of OmpV gave rise to the production of mature OmpV. The efficiency, however, decreased with progressive deletion of the signal sequence within the fusions. The reactivity of various OmpV fusions with antisera raised against purified OmpV and whole bacteria demonstrated the existence of two antigenic domains: one present in the denatured form and another in the membrane-associated form of OmpV. These domains correspond to markedly hydrophilic regions of the protein as would be predicted for surface-exposed epitopes.     

Transport of basic amino acids in Riccia fluitans: Evidence for a second binding site

The transport of several amino acids with different side-chain characteristics has been investigated in the aquatic liverwort Riccia fluitans. i) The saturation of system I (neutral amino acids) by addition of excess -aminoisobutyric acid to the external medium completely eliminated the electrical effects which are usually set off by neutral amino acids. Under these conditions arginine and lysine significantly depolarized the plasmalemma. ii) L- and D-lysine/arginine were discriminated against in favour of the L-isomers. iii) Increasing the external proton concentration in the interval pH 9 to 4.5 stimulated plasmalemma depolarization, electrical net current, and uptake of [¹⁴C]-basic amino acids. iv) Uptake of [¹⁴C]-glutamic acid took place only at acidic pHs. v) [¹⁴C]-histidine uptake had an optimum between pH 6 and 5.5. vi) Overlapping of the transport of basic, neutral, and acidic amino acids was common. It is suggested that besides system I, a second system (II), specific for basic amino acids, exists in the plasmalemma of Riccia fluitans. It is concluded that the amino-acid molecule with an uncharged side chain is the substrate for system I, which also binds and transports the neutral species of acidic amino acids, whereas system II is specific for amino acids with a positively charged side chain. The possibility of system II being a proton cotransport is discussed.Abbreviation AiB -aminoisobutyric acid     

Clinical and immunological evaluation of 20 patients with advanced colorectal cancer treated with high dose recombinant leukocyte interferon-αA (rIFNαA)

Summary A total of 20 patients with advanced colorectal cancer received recombinant leukocyte interferon-A (rIFNA) either chronically (group I: twice a week up to 20×10⁶ IU/m² i.m.) or cyclically (group II: 1–4 periods of 8 consecutive days up to 20×10⁶ IU/m² i.m. daily at 20-days intervals) over a period of 12 weeks. There was 1 partial response, 1 mixed response and 1 patient with stable disease, whilst 17 patients had progressive disease. Median survival was 15.5 months. Survival was significantly shorter when the extent of hepatic disease was >25% (P=0.05), extrahepatic disease was extensive (P<0.005), alkaline phosphatase level was >2× normal (P<0.02), or performance status was <100% (P<0.001). Toxicity consisting mainly of fever, fatigue, anorexia and weight loss was serious in group I and minimal in group II. Administration of rIFNA led to a short lived augmentation of natural killer (NK) cell activity. In the cyclically treated group this was a recurrent phenomenon whereas a marked lasting depression of NK cell activity was seen in chronically treated patients. Interferon- production capacity was significantly stimulated during rIFNA therapy. The differences in toxicity and immunostimulatory effects between the two schedules may be of importance in the design of further studies.This trial was supported in part by Hoffmann-La Roche, Basle     

On the Phospholipid Metabolism of Glial Cell Primary Cultures.

Abstract: Primary cultures were prepared from newborn rat brain. After 16-18 days, they consisted mainly of mature and immature astrocytes and oligodendrocytes, as judged by immunohistochemistry. To study the metabolism of ethanolamine glycerophospholipids, the cells were incubated with 1-[1-³H]alkyl- sn -glycero-3-phosphoethanolamine (1-alkyl-GPE), for 1–20 h. Five main products were formed: 1-alkyl-2-acyl-GPE; 1-alkyl-2-acyksn-glycero-3-phosphocholine (1-alkyl-2-acyl-GPC); 1-alkenyl-2-acyl-GPE (ethanolamine plasmalogen); 1-alkenyl-2-acyl-GPC (choline plasmalogen); and 1-alkyl-glycerol. Acylation of the substrate was the main reaction during the first 3 h of incubation, whereas desaturation to plasmaiogen reached a maximum after 12 h. Greater amounts of radioactivity were observed in the phosphatidylcholine fraction after longer incubation times. Only small amounts of choline plasmalogen were observed. The phosphatidylethanolamine fraction consisted of 26.5% diacyl-, 27.5% alkyl-acyl-, and 46.0% alkenyl-acyl- compounds, whereas the corresponding data for the phosphatidylcholine fraction were 78.5, 16.4, and 5.1%, respectively, after 20 h of incubation. Hydrolysis of the substrate to 1-alkyl-glycerol was a minor reaction.     

Scanning Electron Microscopy of Selected Members of the Streptomyces hygroscopicus Group

Distinctive variations in whole spore morphology and spore surface morphology of Streptomyces hygroscopicus strains, which had been observed previously by the authors by the preshadowed carbon replica technique, were confirmed by observations with the scanning electron microscope.     

Über die Gefässe,die Faszikel und das Bindegewebe der Nerven während des Wachstums

Zusammenfassung Die Gefäße sprossen während zweier Wachstumsphasen in den Nerv ein: bei 11 cm langen Feten liegen 125 Gefäße innerhalb des N. tibialis (R. poplitea), auch bei 23 cm langen Feten finden sich etwa gleichviel Haargefäße im Endoneuralraum. Bei 39 cm langen Feten hat sich die Kapillarzahl etwa verdreifacht. Die Kapillarzahl pro Quadratmillimeter Endoneuralraum ist tabellarisch zusammengefaßt, die kritische Schichtdicke für einzelne Altersstufen errechnet worden.Bereits beim 11 cm langen Feten sind innerhalb des Nerven zarte Septen zu erkennen, aus denen sich bei 16 cm langen das Stratum lamellare perineurii entwickelt hat. Die Zahl der Lamellen vermehrt sich während des intrauterinen Lebens bis auf fünf. Das Stratum fibrosum perineurii et epineurii entwickelt sich erst beim über 35 cm langen Feten. Als erste Bindegewebsstruktur legen sich Teile des interfaszikulären Bindegewebes in Form von dreieckigen Zwickeln um die größeren Nervengefäße. Gleichzeitig runden sich die vorher eckig begrenzten Nervenfaserbündel ab. Während des intrauterinen Wachstums verdicken sich die Faszikel stetig. Allerdings schwanken Zahl und Durchmesser der Faszikel eines Nervs erheblich (Tabelle 2).Das Nervenbindegewebe nimmt während des Wachstums kontinuierlich zu (Tabelle 3). An der Umbiegungsstelle des N. tibialis sind die Faszikel vermehrt und verkleinert. Außerdem lassen sich mehr Bindegewebsanteile am Nervenquerschnitt ermitteln (Tabelle 4).In Injektionspräparaten von Nerven alter Menschen sind endoneurale Degenerationsherde (Renautsche Körperchen) aufgefunden worden. Da innerhalb der betroffenen Faszikel die Kapillarzahl um die Anzahl der Degenerationsherde vermindert ist, wird angenommen, daß diese Gebilde untergegangen und nekrobiotisch veränderten Kapillaren entsprechen.Diese Deutung wird gestützt durch Befunde an Kapillaren in der Umgebung der Degenerationsbezirke, deren Grundhäutchen verdickt und hyalinisiert sind.Im gelähmten Nerv nimmt das Bindegewebe relativ zur schrumpfenden Nervensubstanz zu.Herrn Professor Dr. Fritz Wassermann zum 80. Geburtstag in Verehrung gewidmet.     

Inhibition of Swarming of Proteus by Sodium Tetradecyl Sulfate, β-Phenethyl Alcohol,and p-Nitrophenylglycerine

The effects of sodium tetradecyl sulfate (STS), β-phenethyl alcohol (PEA), and p-nitrophenylglycerol (PNPG) on motility, swarming, flagellation, and growth of Proteus were examined. Growth-inhibitory concentrations (GIC) and swarming-inhibitory concentrations (SIC) were determined. A characterization of the swarming-inhibitory efficacy of these compounds was based on their GIC/SIC ratio and their concentration inhibition curves. Using the homologous series of sodium alkyl sulfates as a standard reference, we showed that PNPG was more effective than STS, which was the most effective of the homologous series. PEA was less effective than sodium decyl sulfate but more effective than sodium octyl sulfate. Motility tests in liquid medium and electron microscope investigations indicated that the modes of action of the three compounds, all of which effectively inhibit the swarming of Proteus, are different. Whereas STS and PEA inhibit swarming by inhibition of motility, PNPG seems to act on the swarming mechanism sensu strictori, without impairment of motility. STS immobilizes by inhibition of flagellum formation or by some lytic action on the flagella already synthesized. PEA acts by impairing flagellar function, but leaves the flagella morphologically intact.     

U-21,963, a New Antibiotic: I. Discovery and Biological Activity

A new antibiotic, U-21,963, is produced by a new strain of Trichoderma viride. Antibiotic activity can be demonstrated against both gram-positive and gram-negative bacteria and also against a wide variety of fungi. U-21,963 is not cross-resistant with other commonly used antibiotics. U-21,963 afforded no protection against Klebsiella pneumoniae, Streptococcus pyogenes, or Staphylococcus aureus when it was injected subcutaneously into mice.