Interactions of the high-mobility-group-like Ceratitis capitata C1 proteins with DNA

We have studied the interactions of the high-mobility-group-like proteins (C1a1, C1a2 and C1b) from the fruit fly Ceratitis capitata with DNA. Nitrocellulose filter binding assays, thermal denaturation studies and spectrofluorimetry of the complexes revealed the existence of specific and nonspecific interactions. Thermal denaturation curves showed that the three proteins stabilized the DNA, thus suggesting a preferential binding to double-stranded DNA. The calculation of the thermodynamic parameters of the interactions showed that the nonspecific bindings were characterized by low association constants (Ka) with values ranging from 2.7 X 10(4) M-1 to 2.0 X 10(6) M-1. Also, the cooperativity of these interactions was relatively high (cooperativity factor, w, values ranging over 20-35), and the number of nucleotides involved was low (1-3 base pairs). On the other hand, the existence of specific interactions between C1 proteins and DNA was suggested by two facts: the retention of C. capitata [3H]DNA in nitrocellulose filters was only a low percentage of total input DNA and there was a marked size dependence of the binding (25% retention of a 40-kb DNA and only 3% retention with a DNA of 1 kb). The specific bindings had higher Ka values than the nonspecific ones, and they also were cooperative. Some differences were observed between C1b and the C1a proteins about the way they interact with C. capitata DNA.     

The relationship between the transport of glucose and cations across cell membranes in isolated tissues XI. The effect of vanadate on 45Ca-efflux and sugar transport in adipose tissue and skeletal muscle

(1) The effects of vanadate of hexose transport, ⁴⁵Ca-exchange and (Na⁺, K⁺)-contents have been characterized in isolated adipose tissue and skeletal muscles of the rat. (2) In whole epididymal fat pads, vanadate (0.5–5.0 mM) markedly stimulated the uptake of 2-deoxyl[¹⁴C]glucose as well as the efflux of $\text{3-O-[}{}^{14}\text{C}\text{]}\text{methylglucose}$. (3) Within the same concentration range, vanadate induced an early increase in ⁴⁵Ca-washout from preloaded fat pads. The maximum increases in the fractional losses of $\text{3-O-[}{}^{14}\text{C}\text{]}\text{methylglucose}$ and ⁴⁵Ca were significantly correlated ($\text{P < 0.001}$, $\text{r = 0.98}$). (4) In extensor digitorum longus and soleus muscles, vanadate (0.5–5.0 mM) stimulated the efflux of $\text{3-O-[}{}^{14}\text{C}\text{]}\text{methylglucose}$ and this effect was preceded by a rise in the washout of ⁴⁵Ca. The maximum increases in the fractional losses of $\text{3-O-[}{}^{14}\text{C}\text{]}\text{methyglucose}$ and ⁴⁵Ca were significantly correlated ($\text{P < 0.005}$, $\text{r = 0.98}$). (5) In extensor digitorum longus and soleus muscles, vanadate increased K⁺-contents and decreased Na⁺ contents. (6) The stimulation of ⁴⁵Ca-washout presumably reflects an increase in the cytoplasmic Ca²⁺ level, brought about by an inhibitory effect of vanadate on the Ca²⁺-sensitive ATPase of the sarcoplasmic or the endoplasmic reticulum. As demonstrated for most other insulin-like agents (Sørensen, S.S., Christensen, F. and Clausen, T. (1980) Biochim. Biophys. Acta 602, 433–445), the stimulating effect of vanadate on glucose transport appears to be associated with or mediated by a rise in the cytoplasmic Ca²⁺ level.     

Medullary structure differences in Gelidium and Pterocladia (Gelidiales, Rhodophyceae): Taxonomic meaning

Study of the apical portions of vegetative thalli of 21 species of the genera Gelidium and Pterocladia (Gelidiales-Rhodophyta) revealed the existence of six patterns of medullary structure. Each pattern is characterized by the organization of the medullary tissue and the changes in cellular dimensions from apex to subapex. These characters can be used to separate groups of species within each genus.     

The Demand for Iodine and Bromine of three Marine Brown Algae grown in Bacteria-free Cultures

Three marine brown algae have been cultivated with different additions of iodine and bromine in bacteria-free cultures. Ectocarpus jasciculatus appeared to have an absolute demand for iodine and was inhibited by a concentration of 64 μmol of KJ per 1. Lithosiphon pusillus had the best growth in the highest concentration tested (64 μmol/1) but there was always some growth in the series without iodine. Additions could be made either as inorganic iodine or as organically bound iodine. Additions of KJ to a culture medium consisting of vitamin-free Asp 6 F with B₁₂ (1 μg/1) and kinetin (20 μmol/1) remarkably increased the growth of the zoospores of Pylaiella litoralis. Lithosiphon pusilius proved to be indifferent to bromide additions in media containing KJ. In media lacking KJ addition of 1 μmol of KBr per 1 is stimulating but higher concentrations of KBr are inhibiting. The inhibiting effect is overcome by iodide addition.     

89. Marianne Mix: Zur Feinstruktur der Zellwände in der Gattung Penium (Desmidiaceae

Die Zellwände von Penium spirostriolatum, P. margaritaceum und P. cylindrus var. attenuatum zeigen im Elektronenmikroskop eine an das Kieselsäureskelett der Diatomeen erinnernde, maschenartig strukturierte Außenschicht, wie sie bisher von keiner anderen Desmidiacee oder Mesotaeniacee bekannt ist (Maschenweiten 220 bis 250 nm). Die lichtmikroskopisch wahrzunehmenden Längsstreifen (P. spirostriolatum) oder Punkte (P. margaritaceum, P. cylindrus var. attenuatum) stellen zusätzliche leistenförmige oder warzenartige Wanderhebungen dar. Unter der netz- oder maschenartig strukturierten Außenschicht liegt die Primärwand, die in Streutextur angeordnete Mikrofibrillen besitzt. Eine ?Häutung” findet in der Gattung Penium nicht statt. Als innerste Wandschicht folgt die Sekundärwand, die — wie bei den Vertretern des Cosmarium-Typs — aus Bändern parallel gelagerter Mikrofibrillen besteht. Poren sind nicht vorhanden. Entstehung, Struktur und Funktion sowie die Bedeutung des markanten Netzwerkes der Außenschicht für die Abgrenzung der Penien gegenüber ähnlich geformten Desmidiaceen und Mesotaeniaceen werden diskutiert.     

2-Phenylethyl ester and 2-phenylethyl amide derivative analogues of the C-terminal hepta- and octapeptide of cholecystokinin

Syntheses of analogues of the C-terminal octa- and heptapeptide of cholecystokinin are described. These analogues were obtained by replacing the C-terminal phenylalanine residue by 2-phenylethyl alcohol or by 2-phenylethylamine derivatives and by replacing the tryptophan residue by a D-tryptophan. The CCK-derivatives were tested for their ability to inhibit binding of labeled CCK-8 to rat pancreatic acini and to guinea pig brain membranes, and for their action on stimulation of amylase release from rat pancreatic acini. Some of these derivatives appeared to exhibit only part of the CCK-activity on amylase release, the D-Trp analogues behaving as CCK-antagonists.     

Design and operation of a completely automated Beckman microsequencer

A unique, efficient, and inexpensive system has been designed and built for the automatic conversion of anilinothiazolinone derivatives extracted from a Beckman spinning-cup sequencer with subsequent on-line high-pressure liquid chromatography separation of the phenylthiohydantoin derivatives. The Auto Converter-Auto Sampler system is controlled by a tape programmer or microprocessor and operates by transfer of the sample from the conversion vial into an HPLC injection loop by nitrogen pressure. Incorporation of a minor programming change on the sequencer allows the introduction of nitrogen vapor into the spinning cup during phenylisothiocyanate coupling. These modifications have resulted in a completely automated subnanomole protein sequencer.     

Design of a gas chromatograph with parallel radioactivity and mass spectrometric detection : Application to the identification of the major metabolite of d-limonene associated with α2u-globulin

A Perkin Elmer 3920 gas chromatograph, equipped with a versatile inlet system (i.e. an injector/trap), was interfaced to a radioactivity detector and a mass-selective detector (H/P 5970B) to identify ¹⁴C-labeled compounds. The use of a pre-trap as a demountable, programmable-temperature injector, in conjunction with the injector/trap, allowed the introduction of 0.5-ml samples of rat kidney cytosol extracts to 0.32 mm I.D. capillary columns. The instrumentation greatly facilitated the identification of the major radiolabeled metabolite of d-limonene associated with the male rat-specific protein α2u-globulin as 1,2-cis-d-limonene oxide.     

Characterization of the Glycolipid Associated with Alzheimer Paired Helical Filaments

Abstract: In the present study, analytical techniques including gas chromatography/mass spectrometry (GC/MS)-assisted carbohydrate linkage-analysis, one- and two-dimensional NMR, and matrix-assisted laser desorption/ionization time of flight mass spectroscopy (MALDI-MS) have been used to characterize the structure of the glycolipid associated with the paired helical filaments (PHF) isolated from the neurofibrillary tangles of Alzheimer's diseased brain. The ¹H NMR spectrum of acid-hydrolyzed protein-resistant core PHF (prcPHF) displays resonances that can be assigned to fatty acid and glucose. There are no resonances present that would indicate the presence of protein, amino acids, or a sphingosine base. Using two-dimensional homonuclear correlated spectroscopy, homonuclear Hartmann-Hahn, and heteronuclear multiple quantum coherence experiments, resonances in the ¹H and ¹³C NMR spectrum of native PHF were assigned to a nonreducing terminal α-1,6-glycosidically linked glucose, an internal α-1,6-linked glucose, and an α-1,2,6-linked glucose. The narrow line-widths observed for these residues suggest that they arise from glucose residues undergoing rapid segmental motion. The carbohydrate portion of the PHF-associated glycolipid was analyzed using GC/MS linkage analysis and confirmed the presence of terminal and internal α-1,6-linked glucose and α-1,2,6-linked glucose in a molar ratio of 2:1:1. Three components of the PHF-associated glycolipid fraction having masses 2,416, 2,325, and 2,237 Da were observed using MALDI-MS. The least abundant, heavier mass component (2,416 Da) was best fit to a structure with a tridecamer of glucose having a single esterified C₂₀ fatty acid (Glc₁₃ + C₂₀ or Glc₁₃ + C_20:1), whereas the more abundant, lower mass components were best fit to noncovalently associated glycolipid dimers, each with a glucose pentamer or hexamer having two C₁₄, C₁₆, or C₁₈ esterified fatty acids {D[(Glc₅ + C₁₈) + (Glc₆ + C₁₆)] or D[(Glc₅ + C₁₄) + (Glc₆ + C₁₄)]}. The ratio of glucose to fatty acid calculated from these best-fit structures of the more abundant mass components (5.5 ± 1.1:1.0) is in reasonable agreement with the same ratio calculated from peak integrations in the NMR spectra of acid-hydrolyzed prcPHF (6.2 ± 1.6). Structural similarities between PHF-associated glycolipid and other glycolipid amphiphiles known to form PHF-like filaments indirectly suggest that this unique glycolipid may be an integral component of the PHF suprastructure.