Non-receptivity for kappa phage of kappa-lysogenic Serratia and reactions to superinfection of receptive cells with a mutant prophage

Summary l_I-lysogenic cells of Serratia marcescens as opposed to l_I ⁺-lysogenic cells, are receptive to further infection. After superinfection with wild type or several clear plaque mutants killing and lytic response were observed to a varying extent. From some of the surviving cells doubly lysogenic colonies with a l_I ⁺ and a l_I prophage could originate, l_I ⁺ being dominant and the cells therefore non-receptive. By this property, combined with a special color reaction, the colonies could be easily screened. Evidence is presented that the l_I ⁺ gene product probably does not interfere with the formation of new phage receptors but that under its influence receptors are masked.Two mutants resembling int^- mutants are described which only rarely give double lysogenization and prophage substitution following superinfection. The phage-coded function normally achieving these reactions is likely to work constitutively after superinfection. Transduction experiments performed with one of the two mutants pointed at integration of prophage into the host DNA near to the trp gene.Abbreviations moi multiplicity of infection - OD optical density - NG N-methyl-N-nitro-N-nitrosoguanidine - NB nutrient broth - BS buffered saline - EMB eosmemethylene blue - leu leucine - met methionine - pro proline - trp tryptophan     

Genetic studies with two prophages naturally resident in Serratia marcescens HY

Summary Serratia marcescens HY was cured of two native prophages, and y. Curing occurred after infection with temperate phage , but the cured strains did not become -lysogenic. One of them has been simultaneously cured of both and y. Recognition of cured colonies was based on their loss of immunity towards the respective phage. Whereas plates on the singly cured strains, it does not plate on the doubly cured strain. However, infection of it with leads to a limited phage multiplication, the average burst size being low and only part of the infected cells producing phage at all. The ability of the strain to serve as indicator for can be restored by relysogenization with either or y. In addition, some further relations between , , and y are reported in this paper.Abbreviations moi multiplicity of infection - A absorbance (optical density) - NB nutrient broth - BS buffered saline - EMB eosine methylene blue - thy thymine - leu leucine This work was supported by the Deutsche Forschungsgemeinschaft. The technical help of Miss A. Varela and Mrs. I. Steiger in some experiments is appreciated.     

On the probability of interaction between elementary radiation-induced chromosomal injuries

Summary Within the Theory of Dual Radiation Action, the heuristically useful function,(), that two energy depositions, a distance apart, will result in observable damage can be written in terms of two more fundamental quantities: One,s(), describes the structure of the sensitive matrix of the cell. The other,g(), describes the probability that two elementary injuries, a distance apart, will combine to produce observable damage. A priori, the known enhancement exhibited byy() at nanometer separations could be due to an enhancement ofs(),g() or both. For the endpoint of chromatid exchanges in Chinese hamster cells,() has been evaluated from experimental data ands() from a model system. From theseg() has been estimated and is roughly constant below 1 µm, decreasing rapidly at larger separations. Thus the enhanced short-range effect appears to be a function more of the spatial characteristics of the target rather than the probability of damage interaction.     

Genetic polymorphism at the mouse immunoglobulin J ϰ locus (Igk-J) as demonstrated by southern hybridization and nucleotide sequence analysis

Comparison of the nucleotide sequences of the C.C58 M75 myeloma chain gene and the BALB/c germ-line J segments suggested that the J regions of C.C58 and BALB/c might be distinguished by restriction enzyme polymorphisms. This was shown to be the case in Southern hybridizations of Hinf I and Ace I digests of liver DNA from these and other strains with a J-specific probe. Tests of a wide variety of inbred, congenic, recombinant, and recombinant-inbred strains provided evidence for three alleles, Igk-J ^a, Igk-J ^b, and Igk-J ^c, the type strains for which are C58/J, BALB/c, and SJL/J, respectively. Analysis of the B6.PL(85NS) congenic strain suggests that the Igk-J locus lies in the neighborhood of the Lyt-2/Lyt-3 loci, approximately 0.30 cM from the V gene segment determining the Igk-VSer and Igk-Efl polymorphisms. Finally, nucleotide substitutions lead to amino acid sequence differences between the C.C58 M 75 gene and the BALB/c germ line in J2 and J4. Two of these substitutions reflect true germ-line differences, raising the possibility that idiotype differences observed among strains could reflect J as well as V differences.     

Use of the crossflow-microscreen technique for SCP production from dilute substrates

Summary A crossflow-microscreen cultivation technique was successfully used to select and maintain an easily harvestable microbial culture with a limited number of species under non-aseptic conditions in diluted cheese whey. The microbial selective pressure exerted by the system could be manipulated by varying the hydraulic () and mean cell () residence times. The optimum system parameters were =1 h and =10 h, resulting in a selected microbial population comprising three species only, namely Geotrichum candidum, Streptococcus cremoris and Leuconostoc lactophilum. The amino acid profile of the SCP produced compared favourably with other types of protein. The crossflow-microscreen technique makes SCP production possible from dilute, waste organic effluents.     

Metabolism of a phenylcoumaran substructure lignin model compound in ligninolytic cultures of Phanerochaete chrysosporium

The degradation of the phenylcoumaran substructure model compound methyl dehydrodiconiferyl alcohol by the white-rot wood decay fungus Phanerochaete chrysosporium was investigated using culture conditions optimized for lignin oxidation. Initial attack was in the cinnamyl alcohol side chain, which was oxidized to a glycerol structure. This was subsequently converted by loss of the two terminal carbon atoms, C and C, to yield a C-aldehyde structure, which was further oxidized to the C-acid compound. The next detected intermediate, a phenylcoumarone, was produced by double bond formation between C and C, and oxidation of the C-alcohol to an aldehyde group. Further oxidation of C to an acid yielded the next intermediate. The final identified degradation product was veratric acid. No products from the 5-substituted aromatic ring, and no phenolic products, were found. The initial glycerol-containing intermediate was a mixture of the threo and erythro forms, and no optical activity could be found, suggesting that its formation might have involved nonstereospecific C-C epoxidation followed by non-enzymatic hydrolysis of the epoxide.Abbreviations TLC thin layer chromatography - LDA lithium diisopropyl amide - DDQ 2,3-dichloro-5,6-dicyanobenzoquinone - MS mass spectrometry - UV ultraviolet spectroscopy     

Stability of fumarase activity of Brevibacterium flavum immobilized with ϰ-carrageenan and Chinese gallotannin

Summary In order to improve L-malic acid productivity by Brevibacterium flavum immobilized with -carrageenan, addition of Chinese gallotannin to the immobilization medium was investigated. As the results show, the optimal concentration of Chinese gallotannin was 0.1% (w/v). Fumarase activity and the stability of this improved preparation were higher than in one with only -carrageenan. Addition of Chinese gallotannin was more advantageous to stability towards ethanol than addition of polyethyleneimine. The L-malic acid productivity of the immobilized cells at 37°C was 42.2 kg/h per 1,000 l column, and increased threefold compared with that of B. flavum immobilized with only -carrageenan, and was 25 times that of B. ammoniagenes immobilized with polyacrylamide. Persimmon tannin also increased the stability of fumarase.     

Determination of the backbone torsion angle ɛ in nucleic acids

Summary The multiplet structure of cross peaks in double-quantum-filtered COSY NMR spectra is analysed for those resonances that include passive heteronuclear couplings. Interestingly, the cross peak involving the sugar-ring protons H2 and H3 in nucleic acids display an E.COSY-type appearance exclusively when the backbone torsion angle (C4-C3-O3-P) adopts a gauche(-) conformation. This observation allows an unambiguous analysis of the conformation around , without the knowledge of ³J_cp coupling constants.     

An alpha-L-fucosidase from Thermus sp. with unusually broad specificity

An -L-fucosidase (E.C. 3.2.1.51) exhibiting a wide aglycon specificity expressed in ability of cleaving 1 6-, 1 3-, 1 4-, and 1 2-O-fucosyl bonds in fucosylated oligosaccharides, has been isolated from culture filtrate of Thermus sp. strain Y5. The -L-fucosidase hydrolyzes p-nitrophenyl -L-fucopyranoside with V _max of 12.0 ± 0.1 M/min/mg and K _m = 0.20 ± 0.05 mM and is able to cleave off about 90% of total L-fucose from pronase-treated fractions of fucosyl-containing glycoproteins and about 30% from the native glycoproteins. The purified enzyme is a tetramer with a molecular mass of 240 ± 10 kDa consisting of four identical subunits with a molecular mass of 61.0 ± 0.5 kDa. The N-terminal sequence showed homology to some -L-fucosidases from microbial and plant sources. Hydrolysis of p-nitrophenyl -L-fucopyranoside occurs with retention of the anomeric configuration. Transglycosylating activity of the -L-fucosidase was demonstrated in reactions with such acceptors as alcohols, N-acetylglucosamine and N-acetylgalactosamine while no transglycosylation products were observed in the reaction with p-nitrophenyl -L-fucopyranoside. The enzyme can be classified in glycosyl hydrolase family 29.     

Application of H(N)CA,CO-E.COSY experiments for calibrating the φ angular dependences of vicinal couplings J(C′i−1,Hi α), J(C′i−1,Ci β) and J(C′i−1,C′i) in proteins

A triple-resonance NMR technique suitable for the determination ofcarbonyl-related couplings in polypeptide systems is introduced. Theapplication of three novel pulse sequences to uniformly¹³C/¹⁵N-enriched proteins yields E.COSY-likemultiplet patterns exhibiting either one of the³J(C_i–1,H_i ), ³J(C_i–1,C_i ) and³J(C_i–1,C_i)coupling constants in the indirectly detected ¹³Cdimension, depending on the passive spin selected. The experiments aredemonstrated with oxidized flavodoxin from Desulfovibrio vulgaris. On thebasis of the J-values measured and the backbone -angles derived from ahigh-resolution X-ray structure of the protein, the three associated Karplusequations were reparametrized. The root-mean-square differences between theexperimental coupling constants and those predicted by the optimized Karpluscurves are 0.41, 0.33 and 0.32 Hz for³J(C_i–1,H_i ),³J(C_i–1,C_i ) and³J(C_i–1,C_i),respectively. The results are compared with the Karplus parameters previouslypublished for the same couplings.     

Genetic variation in the subunits of globulin-1 storage protein of French bean

Summary Charge and molecular weight heterogeneity of globulin-1 (G1) polypeptides of the bean, Phaseolus vulgaris L., were revealed by sodium dodecyl sulphate-polyacrylamide gel electrophoresis (SDS-PAGE). Different bean cultivars were classified into three groups: Tendergreen, Sanilac, and Contender on the basis of their protein subunit composition. Nine distinct major bands: 51,49, 48.5,48^T, 48^S, 47, 45.5, 45^S, and 45^C, and two minor bands: 46^T and 46^S were found to account for the three profiles seen on one-dimensional SDS-PAGE. Two-dimensional analysis revealed these eleven protein bands to be composed of a minimum of fourteen distinct protein subunits. The Tendergreen and Sanilac types differ in their G1 polypeptide composition. The protein patterns of the Contender types are intermediate, containing many protein subunits found in the patterns of the Tendergreen and Sanilac types suggesting a genetic and evolutionary relationship.     

Carrageenans in the gametophytic and sporophytic stages of Chondrus crispus

Summary The morphologically similar sporophytic and gametophytic plants of Chondrus crispus Stackhouse were examined and it was shown that the former contain -carrageenan. The gametophytes contain - and two additional carrageenans which are KCl-soluble and may comprise up to 25% of the total carrageenan. After alkaline modification, these KCl-soluble components were separated into a gel and a soluble carrageenan. The gel was indistinguishable from -carrageenan and presumably was derived from -carrageenan while the KCl-soluble fraction possessed a unique infrared spectrum easily distinguished from alkali-modified -carrageenan. This appears to represent a third carrageenan in the gametophytes.Our observations suggest that the biologically separate plants of C. crispus exhibit distinctive patterns of sulfation of their galactans. The sporophytes add SO₄ ^2- at C₂ of the precursor, whereas the gametophytes appear to add it principally at the available C₄ positions. Both types of plant are capable of sulfating at C₆ of the 4-linked galactose unit.Issued as NRC No. 13119.     

Elongation factor 2 as a target for selective inhibition of protein synthesis in vitro by the novel aromatic biasamidine

By the formation of cGMP the NO-sensitive guanylyl cyclase plays a key role within the NO/cGMP signaling cascade involved in vascular regulation and neurotransmission. The prosthetic heme group of the enzyme acts as the NO sensor, and binding of NO induces conformational changes leading to an up to 200-fold activation of the enzyme. The unexpected fast dissociation half-life of NO of a few seconds is fast enough to account for the deactivation of the enzyme in biological systems. YC-1 and its analogues acting as NO sensitizers uncovered a new pharmacologically and conceivably physiologically relevant regulatory principle of the enzyme.Two existing isoforms of the heterodimeric guanylyl cyclase (₁₁, ₂₁) are known that are functionally indistinguishable. Up to now, the NO-sensitive guanylyl cyclase has been considered as a soluble enzyme. However, recent evidence about the ₂₁ isoform interacting with a PDZ domain of the postsynaptic scaffold protein PSD-95 suggests that the ₂ subunit directs a membrane association of this isoform. The interaction with PSD-95 locates the ₂₁ isoform in close proximity to the NO-generating NO synthase thereby enabling the NO sensor to respond to locally raised NO concentrations.     

Spontaneous chlorophyll mutants of Pennisetum americanum: Genetics and chlorophyll quantities

Summary Thirteen spontaneously occurring chlorophyll deficient phenotypes have been described and their genetic basis was established. Ten of these — white, white tipped green, patchy white, white virescent, white striping 1, white striping 2, white striping 4, fine striping, chlorina and yellow virescent showed monogenic recessive inheritance and the remaining three — yellow striping, yellow green and light green seedling phenotypes showed digenic recessive inheritance. The genes for (i) white tipped green (wr) and yellow virescent (yv) and (ii) patchy white (pw) and white striping 1 (wst 1) showed independent assortment. Further, the genes for white (w), white tipped green (wr) and yellow virescent (yv) were inherited independently of the gene for hairy leaf margin (Hm).In the mutants — white tipped green, patchy white, white striping 1, white striping 2, fine striping, chlorina, yellow virescent, yellow striping, yellow green and light green phenotypes total quantity of chlorophyll was significantly less than that in the corresponding controls, while in white virescent there was no reduction in the mature stage. For nine of the mutants the quantity of chlorophyll was also estimated in F₁'s (mutant x control green). In F₁'s of six of the mutants — white tip, patchy white, chlorina, yellow virescent, fine striping and yellow striping the quantity of chlorophyll was almost equal to the wild type. In the F₁'s of three of the mutants — white striping 1, white striping 2 and light green an intermediate value between the mutant and wild types was observed. In yellow virescent retarded synthesis of chlorophyll, particularly chlorophyll a was observed in the juvenile stage. Reduced quantity of chlorophyll was associated with defective chloroplasts. In the mutants — white tipped green, white virescent, fine striping, chlorina, yellow striping, yellow green and light green defective plastids were also observed. In patchy white secondary destruction of chlorophylls and the presence of defective plastids were found to be associated with reduced chlorophyll quantity at maturity.Paper chromatographic studies of leaf flavonoids revealed some variation between the inbreds, but there were three common spots, 7, 8 and 9, except for PDP in which the spot 8 was absent. Chlorophyll deficient mutants differed from their respective controls in the absence of one or more of the spots present in the controls and in the presence of new spots in some of the mutants.Most of the chlorophyll mutants showed higher survival rate in the Kharif season than in Rabi season which was attributed to the higher mean day temperature and longer day light period in the Kharif season than in Rabi season.     

Interactions among phospholipids of guinea pig rough microsomes,effect of fat deficiency

Summary The fatty acid composition and the steady-state fluorescence anisotropy (r_s) of 1,6-diphenyl-1,3,5-hexatriene (DPH) were determined for each of the five major phospholipid (PL) classes present in the liver rough microsomes (RM) of guinea pigs fed with control and fat-deprived diets. In order to obtain information about PL-PL interactions and their contribution to the overall membrane fluidity the experimental r_s of phospholipid mixtures were compared to the molar weighed average values of the individual phospholipid r_s values. The PL ratios in the mixtures were the same to those found in the RM membranes. Binary mixtures of phosphatidylcholine (PC) with phosphatidylethanolamine (PE), phosphatidylserine (PS), phosphatidylinositol (PI) and sphingomyelin (SM) show higher values of r_s than those estimated from the individual component parameters indicating a rigidizing interaction. The rigidizing effect of PE was also observed when this phospholipid was sonicated with mixtures of PC with PS and PI. However, no rigidizing effect of PE was observed in the PC bilayers when SM was included in the composition suggesting that PE-SM interactions prevent rigidizing effects of PE. Besides, in spite that PC-PI and PC-PS mixtures have rigidizing interactions, the incorporation of PI and PS to PC-PS and PC-PI mixtures, respectively, have a fluidizing effect. In consequence, phospholipid polar head groups interact in RM membranes modifying the molecular packing and/or the rotational diffusion of acyl chains. The complexity and variety of constituent phospholipids could prevent major changes in the fluidity. The comparison of results obtained with PL mixtures of control and fat-deficient animals indicate that a change in the number of double bonds does not evoke a significant difference between either the rigidizing of fluidizing effects. However, there is a general tendency indicating that phospholipids with higher double bond index evoke lower rigidizing and fluidizing interactions. Moreover, PL of animals fed a fat-deficient diet have less fluidity than those of control animals.Member of the Carrera del Investigador Científico, Consejo Nacional de Investìgaciones Científicas y Técnicas, Argentina.     

Indignant suicide in the Pacific: an example from the Toraja highlands of Indonesia

This paper describes and analyzes a type of Toraja (South Sulawesi, Indonesia) suicide in which a person kills him or herself after having been slighted or offended, usually by a close family member. Comparing and contrasting such suicides to similar types found elsewhere in Austronesia-speaking Oceania, the paper argues that self-inflicted deaths of this nature are not so much anomic, as suggested by some analysts, as indignant; they are committed by persons who feel that they have been severely mistreated or abused according to traditional notions of reciprocity, mutual aid, and the dangers of frustrated desire. The paper concludes by suggesting that Durkheim may have underestimated the frequency and importance of indignant suicide in traditional societies and that, conversely, contemporary analysts may be underestimating the importance of traditional norms and values in accounting for the high rates of suicide found in many parts of the Pacific today.     

Study of amino acid formation during palmitate oxidation in rat brain mitochondria

The interrelation of palmitate oxidation with amino acid formation in rat brain mitochondria has been investigated in purified mitochondria of nonsynaptic origin by measuring the formation of aspartate, -ketoglutarate, and glutamate during palmitate oxidation, and also by assaying¹⁴C-products of [1-¹⁴C]palmitate oxidation. Oxidation of palmitate (or [1-¹⁴C]palmitate) resulted in the formation of aspartate (or¹⁴C-aspartate), and the oxidation was inhibited by aminooxyacetate (an inhibitor of transaminase), Palmitate oxidation also resulted in -ketoglutarate formation, which was sensitive to the effect of aminooxyacetate. Addition of NH₄Cl was found to increase¹⁴C-products and formation of -ketoglutarate, whereas glutamate formation was not increased unless the rate of palmitate oxidation was reduced by 50% by aminooxyacetate or -ketoglutarate was added exogenously. Exogenous -ketoglutarate was found to decrease¹⁴C-products, but not aspartate formation. These results indicated that palmitate oxidation was closely related to aspartate formation via aspartate aminotransferase. During palmitate oxidation without aminooxyacetate or added -ketoglutarate, however, -ketoglutarate was not available for glutamate formation via glutamate dehydrogenase. We discuss the possibility that this was because (a) oxidative decarboxylation of -ketoglutarate to form succinyl-CoA was favored over glutamate formation for the competition for -ketoglutarate in the same pool, and (b) the pool of -ketoglutarate produced in the aspartate aminotransferase reaction did not serve as substrate for glutamate formation.     

Temperate and virulent forms of phage theta attacking Bacillus licheniformis

Summary Clear-plaque phage _c, attacking bacitracin-producing strains of B. licheniformis, yields spontaneous temperate mutants at high frequency; the temperate mutants fall into several classes phenotypically different in plaque morphology and properties of lysogenised bacteria. The most common phenotype ₃ has DNA restriction fragment patterns identical with those of the parent _c; some less common temperate forms, i.e. ₁ and ₂, produce different restriction fragment patterns, sugesting that a part of the original _c DNA has been reorganized or replaced by some foreign genetic material. The changed fragment pattern remains stable upon subsequent passaging of the phage or of the lysogenic bacteria. Neither class of temperate phage mutants gives clearplaque revertants at measurable frequency. Lysogenisation of bacteria with any class of temperate phage confers immunity to all temperate forms and to _c; virulent mutants _vir, which plate with 100% efficiency on lysogens for ₁ and ₂ but not for ₃, occur in stocks of _c at a frequency of 10^–7. The mutation from _c to _vir is not accompanied by any change of the restriction fragment patterns of DNA.     

Cohesive single-stranded ends of Streptomyces temperate bacteriophage R4.

Summary The cohesive single-stranded termini of temperate Streptomyces phage R4 were found to be complementary 11 base single-stranded 3-extended DNAs with the sequence: 5-CGCCGTGTCTT-3 3-GCGGCACAGAA-5     

Reduced expression of a distal gene of the prn gene cluster in deletion mutants of Aspergillus nidulans: genetic evidence for a dicistronic messenger in an eukaryote.

Summary Temperature sensitive dnaAts46 mutants, in which initiation of chromosome replication is blocked at 42° C, are unable to maintain a dv plasmid at the permissive temperature unless the plasmid carries a mutation in gene P of the type permitting phage to grow in groP (dnaB) bacteria. The growth rate of dnaAts46 mutants seems to be impaired by the presence of the dvP mutant plasmid.Cold sensitive dnaAcos mutants which overinitiate replication at low temperature and grow normally only at 40° and above, can maintain efficiently dvP ⁺ plasmids as well as dvP mutants. Cold sensitivity of dnaAcos mutants is suppressed by the presence of the plasmid dvP ⁺ and by certain dvP mutants, but not by others.The gene P product seems to act by reducing the initiation potential of both types of dnaA mutants, aggravating the initiation defect in dnaAts46 and correcting the overinitiation of dnaAcos.