Über quantitative Veränderungen „gomoripositiver“ Substanzen in Infundibulum und Hypophysenhinterlappen der Ratte nach beidseitiger Adrenalektomie

Zusammenfassung Bei der normalen weißen Ratte verhält sich die Zona externa des Infundibulum im Gegensatz zur Zona interna infundibuligomorinegativ.Am 7. Tag nach beidseitiger Adrenalektomie treten in der Zona externa gomoripositive Substanzen auf, deren Menge über den 14. Tag nach der Operation hinaus zunimmt.Im supraoptico-hypophysären System ergibt die quantitative Messung eine Entleerung des neurosekretorischen Materials am 3. Tage nach beidseitiger Adrenalektomie. Im Verlauf von 14 Tagen nach dem operativen Eingriff füllt sich das neurosekretorische System wieder bis zu den beim Normaltier ermittelten Werten auf.Die gomoripositiven Granula in der Zona externa inf. sind möglicherweise das morphologische Äquivalent eines Corticotropin-releasing factors.

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On quantitative changes of Gomori-positive substances in the median eminence and neural lobe of the rat hypophysis after bilateral adrenalectomy

Summary In the normal albino rat, the external layer of the median eminence shows a Gomori-negative histochemical reaction as opposed to the internal layer.On the 7th day after bilateral adrenalectomy, Gomori-positive substances appear in the external layer, their amount increasing up to and beyond the 14th day p.o.In the supraoptico-hypophyseal system, quantitative measurements show a depletion of the neurosecretory substance on the 3rd day following bilateral adrenalectomy. This loss of neurosecretory material is restored during the course of 14 days p.o., the amount then corresponding to that found in the normal rat.It is conceivable that the Gomori-positive granules in the outer layer of the median eminence are the morphological equivalent of a CRF.

     

Genetic studies of the ribosomal proteins in Escherichia coli. XI. Mapping of the genes for L21, L27, S15 and S21 by using hybrid bacteria and over-production of these proteins in the merodiploid strains.

Summary Host capacity for growth of single-stranded DNA phages was investigated with several replication mutants of E. coli. In dnaL708, dnaM709 and dnaS707 mutants, multiplication of K was not restricted even at 42°C. In dnaM710 cells, however, growth of K was severely affected at 42°C but not at 33°C. Upon infection of K, parental replicative form was synthesized at the restrictive temperature, whereas subsequent step (replication of progeny replicative form) was blocked in the dnaZ strain. Growth of X174 and 3, as tested by transfection, was also thermosensitive in the dnaM710 mutant but not in the dnaL708, dnaM709 and dnaS707 strains. In contrast with , microvirid phages could grow in E. coli cells bearing the groPC259, groPC756 or seg-2 mutation.This paper is number 15 in the series entitled Sensivity of Escherichia coli to Viral Nucleic Acid     

lambdaimm P22dis: a hybrid of coliphage lambda with both immunity regions of Salmonella phage P22.

Summary Genetically marked and P22 phages were recombined in Escherichia coli-Salmonella typhimurium hybrid WR4028, a host sensitive to infection by both of these phages. Hybrid phages that acquired the immC region of P22, but retained the genes for the protein coat were selected on WR4027 (), a -immune, P22-resistant derivative of WR4028. In these immP22 hybrids, at least the c through P genes of were replaced with functionally related P22 genes. Phage recombinants with more extensive regions of the P22 genome were selected on the double lysogen WR4027 (, immP22). One such hybrid, immP22dis, was determined by heteroduplex analysis to contain approximately 40% of the P22 genome. Genetic studies established that immP22dis possesses the two widely separated immunity control regions of P22 (immC and immI) and that these loci are expressed in E. coli K-12 lysogenic for immP22dis. In addition, immP22dis contains the P22 a1 locus responsible for somatic 0–1 antigen conversion in Salmonella. Although the immP22dis phage particle has the head and tail, the phage genome also carries P22 tail gene 9 as evidenced by the production of free P22 tails. It also has the P22 att site as indicated by the integration of the immP22dis prophage near the proA locus on the bacterial chromosome.     

Bacteriophage lambda replication proteins: formation of a mixed oligomer and binding to the origin of lambda DNA

Summary The purified bacteriophage replication proteins O and P sediment separately in metrizamide gradients of low ionic strength as dimers. Together they interact with each other forming an oligomer, composed of two molecules of O and one molecule of P. The O-P oligomer is active in the in vitro replication of ori-containing DNA.Equilibrium sedimentation in preformed metrizamide density gradients under conditions that separate DNA-protein complexes from free proteins was employed in order to study possible interactions among the replication proteins and ori DNA. It was found that the P protein binds specifically to ori-containing plasmid DNA only in the presence of O protein. About 100 molecules of O and 10 molecules of P form a complex with the ori DNA. The DNA-O-P complex was shown to be active in an in vitro replication system.Since the physical interactions between ori and O and between P and the Escherichia coli dnaB replication protein are well documented, the evidence for a O-P interaction presented in this paper provides the missing link in the molecular mechanism that enables to direct the host replication machinery to the replication of its own DNA.     

Free proline accumulation in maize (Zea mays L.) subjected to prolonged waterlogging

Summary Free proline accumulation was measured in two maize genotypes (Ganga-2 and D747) subjected to waterlogging for three weeks at the knee high stage. The initial content of free proline was same in both the genotypes (0.1 micromole per gram fresh weight of leaves). The free proline content increased in both the genotypes when the plants were subjected to waterlogging. However, Ganga-2 accumulated more free proline than D747. Ganga-2 appeared to be more waterlogging tolerant than D-747.     

Directed integration of an F'' plasmid by integrative suppression: isolation of plaque forming lambda transducing phage for the dnaC gene.

Summary A new approach for isolation of a plaque forming specialized transducing phage is described. It consists of directed transposition of an F plasmid into the gal region of a dnaAts galE ^- Escherichia coli strain by integrative suppression and deletion of the chlD region in order to shorten the distance between the marker of interest on the F and the prophage serving to prepare an LFT¹ lysate.An F danC ⁺ thr ⁺ plasmid was used here and dthr and ddnaC phages were isolated. In addition, pdnaC was obtained from a double lysogen for ddnaC and b2.     

Mutant of Escherichia coli with unusual patterns of rpoB,C expression in response to rifampicin and acridine orange

Summary A mutation located near rpoB (89) in E. coli is responsible for unusual patterns of and (but not L7/L12) synthesis in response to the drugs rifampicin and acridine orange.     

Secondary structure of the entomocidal toxin from Bacillus thuringiensis subsp. kurstaki HD-73

The secondary structure of the toxin fromBacillus thuringiensis subsp.kurstaki (Btk) HD-73 was estimated by Raman, infrared, and circular dichroism spectroscopy, and by predictive methods. Circular dichroism and infrared spectroscopy gave an estimate of 33–40% -helix, whereas Raman and predictive methods gave approximately 20%. Raman and circular dichroism spectra, as well as predictive methods, indicated that the toxin contains 32–40% -sheet structure, whereas infrared spectroscopy gave a slightly lower estimate. Thus, all of these approaches are in agreement that the native conformation of Btk HD-73 toxin is highly folded and contains considerable amounts of both -helical and -sheet structures. No significant differences were detected in the secondary structure of the toxin either in solution or as a hydrated pellet.     

Multiple sex chromosomes in Drosophila miranda: A system to study the degeneration of a chromosome

Drosophila miranda possesses an intriguing sex chromosome constitution. While female metaphase plates have 10 chromosomes (diploid set), in males only 9 chromosomes can be identified. The missing homologue has been translocated to the Y, forming a neo-Y chromosome which is polytenized in the salivary gland cells. This report presents a detailed characterization of DNA, isolated from D. miranda flies. In situ hybridizations, using cRNA transcribed from unfractionated D. miranda DNA, reveal hybridization to the neo-Y with label distributed over the entire chromosome. The original partner of the translocated chromosome, X², is essentially unlabelled. These results suggest that repetitive DNA sequences invade the translocated chromosome. This result is discussed with reference to the hypothesis of degeneration of the Y chromosome, formulated by Muller (1918, 1932a).     

T-cell receptor gene rearrangement and expression in human natural killer cells: natural killer activity is not dependent on the rearrangement and expression of T-cell receptor α, β, or γ genes

To test the hypothesis that the T-cell receptor (Tcr) gene encodes a natural killer (NK) cell receptor molecule, three human NK clones and fresh peripheral blood lymphocytes with NK activity from two patients with a CD16⁺ lymphocytosis were analyzed for rearrangements and expression of the human Tcr , , and genes. Two of the clones displayed distinct rearrangements of their Tcr and genes and expressed mature Tcr , , and l RNA. However, one of the clones and both patient samples displayed marked NK activity but failed to rearrange or express any of their Tcr genes. These findings demonstrate that human natural killer activity is not dependent on Tcr gene rearrangement and expression. In addition, they confirm previous findings concerning the lack of Tcr and gene expression in some natural killer cells. Thus, they suggest the existence of additional NK-specific recognition molecules.     

Spontaneous mutations changing the raffinose metabolism ofLactobacillus plantarum

Lactobacillus plantarum ATCC 8014 grew poorly on raffinose agar plates, but large mutant colonies appeared in high frequency from a thin film of background growth. The -galactosidase and -galactosidase activities ofL. plantarum ATCC 8014 and a mutant strain were studied in static cultures and pH-controlled fermenter cultures. Both -galactosidase and -galactosidase production were inducible in the parental strain; the induction was not needed in the mutant. The -galactosidase activity of both strains was repressed by glucose but not by -methyl-D-glucoside. The mutant phenomenon might be an obstacle in connection to traditionalLactobacillus identification by means of carbohydrate fermentation.     

Normal expression of the viral gene N interferes with growth of bacteriophage lambda in Escherichia coli 15T-.

Summary Growth of and of some lambdoid phages is considerably inhibited on strain 3057 derived from E. coli 15T^-. Mutants of which overcome this inhibition map in gene N. Some of these hty mutants are temperature sensitive for growth on E. coli K12. Thus plating of on strain 3057 allows one to isolate temperature sensitive N mutants. The hty mutants produce less than normal N activity as judged by their low efficiency of plating on a nus ^- host and by the extended latent period of some of them on normal hosts. The inability of strain 3057 to propagate can be at least partially reversed by addition of thymidine to the medium and the growth difference between hty and in 3057 increases with decreasing thymidine concentration. The amount of DNA produced by in 3057 at low thymidine concentration is lower than that produced by hty under the same conditions. Only a small percentage of the DNA produced by in 3057 is packaged into viable phage particles. This suggests that not only produces less DNA in 3057 than hty but that an important part of the DNA in 3057 is in a form which can not be packaged or which is noninfective for other reasons. A hypothesis is discussed that hty mutations enable to grow on E. coli 15T^- at low thymidine concentration because they lead to reduction in the number of single strand nicks in the DNA by reducing the intracellular endonuclease activity. Under permissive conditions conditional lethal N mutants are favored for growth on 3057 over N ⁺ which confirms the idea that N activity or the activity of a gene under N control interferes with growth in 3057 at low thymidine concentration.     

Physiological relationship between the temperate phages lambda and phi80

Summary This work deals with the ability of phage 80 to provide defective mutants of with their missing functions. Functions Involved in Recombination. As shown by others, the Int mechanism of 80 cannot excise prophage . However, 80 efficiently excises recombinants from tandem dilysogens, using its Ter mechanism. Likewise, the nonspecific mechanism Red is interchangeable between 80 and . Maturation of DNA by 80. The Ter recombinants excised by 80 from tandem dilysogens are packaged into a 80 protein coat. This contrasts with the fact, already mentionned by Dove, that 80 is extremely inefficient for packaging phage superinfecting a -lysogen. The latter result is also found when the helper phage is a hybrid with the left arm of (80hy4 or 80hy41 — see Fig. 1). However, the maturation of the superinfecting is much more efficient if the 80hy used as a helper has the att-N region of (like 80hy1). Conversely a with the att-N region of 80 (hy6 — see Fig. 1) is packaged more efficiently by 80 or 80hy4 than by 80hy1. It is suggested that the maturation of chromosome superinfecting an immune cell requires a recombination with the helper phage. Vegetative Functions. Among the replicative functoons O and P, the latter only can be supplied by 80. That N mutants are efficiently helped by 80 does not tell that 80 provides the defective with an active N product; the chromosomes are simply packaged into a 80 coat. This shows that 80 is unable to switch on the late genes of . That neither 80 nor any of the 80hy tested can provide an active N product is shown in a more direct way by their complete failure to help N ^-r₁₄; this phage carries a polar mutation which makes the expression of genes O and P entirely N-dependant. The maturation of a N ^- by 80 contrasts with the fact that mutants affected in late genes (A, F or H) are not efficiently helped by 80. This suggests that the products coded by these genes are not interchangeable between 80 and , and that packaging of DNA into 80 coats is possible but inhibited when late proteins are present in the cell. Activation of the Late Genes. Among the im ₈₀ h ⁺ hybrids tested, only 80hy41 is able to switch on the late genes of a N defective mutant. This hybrid differs from the other hybrids studied here, by the fact that it has the Q-S-R region of (see Fig. 1). The results are consistant with the view that the product of Q gene is sufficient for activating the late genes of a DNA. N would thus control the expression of late genes only indirectly by controlling the expression of gene Q (Couturier & Dambly have independantly reached the same conclusion, 1970). Furthermore the failure of 80 and of the 80hy1 and 80hy4 to activate the late genes of would imply that these phages are unable to provide an Q product active on the chromosome Reciprocally, switches on the late genes of prophage 80hy41, but not of prophages 80hy1 and 80hy4. This suggests that the initiation of late genes expression takes place at a main specific site located in the Q-S-R region of the chromosome. The expression of the late genes would thus be sequential, and proceed through the left arm only when steaky ends cohere. Similar conclusions were reached independantly by Toussaint (1969) and by Herskowitz and Signer (1970).

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Ce travail a été réalisé dans le cadre du contrat d'association Euratom-U. L. B. 007-61-10 ABIB et avec l'aide du Fonds de la Recherche Fondamentale Collective.     

Metabolic cost of sodium transport in toad urinary bladder

Summary The metabolic cost of active sodium transport was determined in toad bladder at different gradients of transepithelial potential, , by continuous and simultaneous measurements of CO₂ production and of transepithelial electric current. Amiloride was used to block active sodium transport in order to assess the nontransport-linked, basal, production of CO₂ and the passive permeability of the tissue. From these determinations active sodium transport,J _Na, and suprabasal CO₂ production, , were calculated. Since large transients inJ _Na and frequently accompanied any abrupt change in , steady state conditions were carefully defined.Some 20 to 40 min were required after a change in before steady state of transport activity and of CO₂ production were achieved. The metabolic cost of sodium transport proved to be the same whether the bladder expended energy moving sodium against a transepithelial electrical potential grandient of +50 mV or whether sodium was being pulled through the active transport pathway by an electrical gradient of –50 mV. In both cases the value of the ratio averaged some 20 sodium ions transported per molecule of CO₂ produced.When the Na pump was blocked by 10^–2 m ouabain, the perturbations of the transepithelial electrical potential did not elicit changes ofJ _Na nor, consequently, of .The independence of the ratio from over the range ±50 mV indicates a high degree of coupling between active sodium transport and metabolism.     

Trehalose synthesis from maltose by a thermostable trehalose synthase from Thermus caldophilus

Purified trehalose synthase from Thermus caldophilus GK24 produced 18–86% trehalose from 10 mM–1 M maltose. The enzyme also catalyzed the conversion of ,-trehalose into maltose but did not act on other disaccharides. The yield of trehalose from maltose by this enzyme increased 30% more at 40°C than at 80°C and was independent of the substrate concentration. The maximum yield of ,-trehalose from 10 mM maltose reached 86% at 40°C. In addition, ,-trehalose was also formed from maltose or ,-trehalose at 3.5% yield at 80°C. © Rapid Science Ltd. 1998     

Bacteriophage lambda DNA-dependent synthesis of endolysin in a membranous cell-free system of E. coli

Summary We have previously shown that a membranous cell-free system derived from uninfected penicillin spheroplasts of E. coli transcribes early and late messenger RNA's from DNA.This in vitro system will also transcribe and translate the endolysin gene R of DNA. The enzyme activity that results from in vitro synthesis corresponds to endolysin (a typical late protein) by several criteria.DNA from C_I857 sus R5 ts 9B and C_I857 sus S7 pgal, mutants carrying nonsense mutations in genes involved in the host lysis, are inactive in the synthesis of endolysin with an extract of non permissive cells, although they are fully active with an extract of permissive cells. Furthermore, suppression of these mutations is entirely dependent on addition of supernatant from suppressor strains.The endolysin synthesis from a thermosensitive C_I mutant is observed at 40°C and not at 30°C. This suggests that the product of C_I gene is formed and acts in the in vitro system at 30°C.Enzymatic activity is detected after a 15 min lag period.Membranes and double stranded DNA are absolutely required for the enzyme synthesis. Ribosomes and supernatant highly stimulate the in vitro system.Inhibitors of RNA, DNA and protein synthesis (actinomycine D; cytosine arabinoside; DNA-ase; and chloramphenicol respectively) will prevent endolysin production when added at zero time. If DNA-ase or actinomycine D are added after 20 min of incubation, only partial inhibition of endolysin synthesis occurs. It is therefore concluded, according to our previous observations, that messengers are stable enough to allow enzyme synthesis after delayed addition of the inhibitors in the in vitro system.It appears that there is a complete regulation in the membranous system like in vivo and which starts with the early and late messenger formation and leads to active late protein synthesis.     

Several phenotypic changes in the cell envelope of Agrobacterium tumefaciens chvB mutants are prevented by calcium limitation

The chvB gene of Agrobacterium tumefaciens encodes a 235 kDa proteinaceous intermediate involved in the synthesis of -1,2-glucan. chvB mutants show a pleiotropic phenotype. Besides not to produce cyclic -1,2-glucan, chvB mutants have been reported to be avirulent, attachment-deficient, and nonmotile. In this study we report additional differences from the parent strain, probably all linked to changes in the cell envelope. This pleiotropic phenotype — except for attachment and virulence — could largely be prevented by growing chvB cells with low levels of calcium. Although a role for -1,2-glucan in osmoadaptation has been proposed, the mode of action of -1,2-glucan is not known. We speculate that in A. tumefaciens -1,2-glucan stabilizes membranes, which would be important especially in hypotonic media containing calcium.Abbreviations Cb carbenicillin - Km kanamycin - TCA trichloroacetic acid - K_av fraction of the stationary gel volume available for diffusion - LPS lipopolysaccharide - SDS-PAGE Sodium dodecyl sulphate polyacrylamide gel electrophoresis     

Effects of high ambient temperatures on the metabolism of West African dwarf goats. I

Thirty-two West African dwarf goats were exposed to temperature treatments: 20, 25, 30, 35, 35, 35, 30, 25, 20°C each lasting three days.Sixteen goats were kept in individual pens (I), the others in two group pens (G). Heat production (HP) and activity were recorded during 48 hours in each temperature treatment.Mean HP and ME intake were similar for G and I animals, but I animals had lower values than G animals at low chamber temperatures and higher values than G animals at high temperatures. Upper critical temperature was between 25°C and 30°C under an increasing T and between 30 and 35°C under a decreasing T. Adaptation of heat production and ME intake to a change in temperature of 5°C required at least six and possibly more than nine days.Diurnal variation in HP was large, up to 44% between extremes. This was largely due to variation in activity.     

Waves in a simple,excitable or oscillatory,reaction-diffusion model

A simple one variable caricature for oscillating and excitable reaction-diffusion systems is introduced. It is shown that as a parameter, , varies the system dynamics change from oscillatory ( > ₀) to excitable ( < ₀) and the frequency of the oscillation vanishes as for ₀. When such dynamics are coupled by continuous diffusion in a ring geometry (1-space dimension), propagating wave trains may be found. On an infinite ring excitable devices lead to unique solitary waves which are analogous to pulse waves. A solvable example is presented, illustrating properties of dispersion, excitability, and waves. Finally it is shown that the caricature arises in a natural way from more general excitable/oscillatory systems.     

The glutamine synthetase gene family of Arabidopsis thaliana: light-regulation and differential expression in leaves, roots and seeds.

Summary Glutamine synthetase (GS) plays an important role in the assimilation of nitrogen by higher plants. We present here a molecular analysis of the GS polypeptides, mRNAs, and genes of Arabidopsis thaliana. Western blot analysis of leaf and root protein extracts revealed at least two distinct GS polypeptides; 43 kDa and 39 kDa GS polypeptides were present in leaves, while only a 39 kDa GS was detected in roots. The 43 kDa GS polypeptide is light-inducible. In etiolated seedlings only the 39 kDa GS was detected. However, upon greening the 43 kDa GS increased to levels comparable to those observed in light-grown plants. Four distinct GS cDNA clones, Atgsl1, Atgsrl, Atgsr2 and Atk6 were isolated and characterized. Their complete nucleotide and deduced amino acid sequences are presented. The coding sequences of the four clones are 70–88% similar while their 5 and 3 untranslated regions exhibit less than 50% similarity. Northern blots of leaf, root and germinated seed RNA revealed that the four cDNAs hybridize to mRNAs which are differentially expressed in the organs of Arabidopsis thaliana. Atgsl1 is leaf-specific and hybridizes to a 1.6 kb mRNA. Both Atgsr1 and Atgskb6 hybridize to 1.4 kb mRNAs which are expressed in both roots and germinated seeds. Atgsr2 hybridizes to a 1.4 kb mRNA, which is primarily expressed in roots with low levels of expression in seeds and leaves. Atgsl1, which represents the leaf-specific mRNA, is induced by light. Atgsl1 mRNA levels increase during the greening of etiolated seedlings while Atgsr1 levels remain constant. Southern blot analysis indicated that the Arabidopsis genome contains at least four and possibly five distinct GS genes.