Hydrogen isotope discrimination in higher plants: Correlations with photosynthetic pathway and environment

Summary The ratio of deuterium to hydrogen (expressed as D) in hydrogen released as water during the combustion of dried plant material was examined. The D value (metabolic hydrogen) determined on plant materials grown under controlled conditions is correlated with pathways of photosynthetic carbon metabolism. C₃ plants show mean D values of-132 for shoots and -117 for roots; C₄ plants show mean D values of -91 for shoots and-77 for roots and CAM plants a D value of-75 for roots and shoots. The difference between the D value of shoot material from C₃ and C₄ plants was confirmed in species growing under a range of glasshouse conditions. This difference in D value between C₃ and C₄ species does not appear to be due to differences in the D value (tissue water) in the plants as a result of physical fractionation of hydrogen isotopes during transpiration. In C₃ and C₄ plants the hydrogen isotope discrimination is in the same direction as the carbon isotope discrimination and factors contributing to the difference in D values are discussed. In CAM plants grown in the laboratory or collected from the field D values range from-75 to +50 and are correlated with ¹³C values. When deprived of water, the D value (metabolic hydrogen) in both soluble and insoluble material in leaves of Kalanchoe daigremontiana Hamet et Perr., becomes less negative. These changes may reflect the deuterium enrichment of tissue water during transpiration, or in field conditions, may reflect the different D value of available water in areas of increasing aridity. Whatever the origin of the variable D value in CAM plants, this parameter may be a useful index of the water relations of these plants under natural conditions.     

An elongated segment of DNA observed between two human α globin genes

Summary Detailed restriction enzyme analysis of the DNA from a Chinese female showed that one of her chromosomes had a >17.5 kb deletion of DNA, including the , 2, and 1 globin genes, which is present in many Southeast Asians with an -thalassemia-1 chromosome. Her normal chromosome had the expected cluster of -like globin genes (5----2-1-3), but the segment of DNA between the two globin genes was elongated by some 0.5–0.7 kb. Analyses of various restriction sites suggested that this normal variant of the human globin gene complex is due to a crossover between a normal chromosome with () and a chromosome with an -thalassemia-2 (–^3.7) and an -21-hybrid gene.     

Ganglioside-cholera toxin interactions: a binding and lipid monolayer study

Summary On t.l.c. plates ¹²⁵I-cholera toxin binds to a disialoganglioside tentatively identified as GD_lb with about 10 times less capacity than to ganglioside GM₁. Binding of labeled toxin to both gangliosides was abolished in presence of excess amounts of unlabeled B subunit. Ganglioside extracts from human or pig intestinal mucosa showed toxin binding to gangliosides GM₁ and GD_1b. In ganglioside-containing lipid monolayers the penetration of the toxin was independent of the ganglioside binding capacity.Abbreviations GM₂ Gal-NAc14Gal(3-2NeuAc)14G1c1Cer - GM₁ Gal3Ga1-NAc14Gal(32NeuAc)14G1c11Cer - GD_1a NeuAc23Ga113Gal-NAc14Gal(32NeuAc)14G1c11Cer - GD1b Gall3Gal-NAcl4Gal(32NeuAc82NeuAc)14Glc11Cer - GT_1b NeuAc23Ga113Ga1-NAcal4Gal(3-2NeuAc82NeuAc)14G1c11Cer - dpPC 1,2-hexadecanoyl-sn-glycero-3-phosphocholine - dpPE 1,2-hexadecanoyl-sn-glycero-3-phosphoethanolamine     

Genetic analysis of resistance to whitebacked planthopper in twenty-one varieties of rice,Oryza sativa L.

Summary The inheritance of resistance to whitebacked planthopper Sogatella furcifera (Horvath) was studied in 21 rice varieties. Reactions of F₁; F₂ and F₃ progenies of the crosses of 21 resistant varieties with the susceptible variety TN 1 revealed that a single dominant gene governs resistance in Mushkan 41, Santhi, Siahnakidar 195, SM2-34, Tirisurkh 251, Zirijowaian 245, 18, 24A, 39, 76 S, 78, 180, 213 B, 267, 293, CI 6037-4, NP97, S39 JKW and Bansphul. In varieties 65 and 274 A, resistance is governed by one dominant and one recessive gene which segregate independently of each other. Tests for allelism with the Wbph 1 gene originally identified in N 22 revealed that the dominant gene present in all the test varieties is the same as Wbph 1. Further studies are required to determine the allelic relationships of the recessive gene found in varieties 65 and 274 A.     

Adoptions expérimentales de larves entre des fourmis de genres différents (II):Myrmica laevinodis Nylander etAnergates atratulus Schenck

Résumé Nous avons fait élever des larves d'Anergates atratulus par des ouvrières deMyrmica laevinodis à 22°C. Pour y parvenir, il n'est pas utile de faire hivernerensemble les larves d'Anergates et les ouvrières deMyrmica. La présence de larves autochtones n'empêche pas lesMyrmica d'élever des larves d'Anergates. Dans toutes les expériences lesMyrmica ont été soumises au fridavant de recevoir des larves d'Anergates. Aucune reine deMyrmica n'a été utilisée dans ces expériences.Sur les 64 larves d'Anergates que nous avons utilisées, 38 se sont transformées en imagos. C'est au début de l'adoption et au moment des métamorphoses que périrent la plupart des 26Anergates perdus. Les femelles vécurent en général 2 ou 3 jours et cherchèrent très tôt à quitter le nid natal. Les mâles vécurent 2 à 3 semaines.

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Summary Larvae ofAnergates atratulus were experimentally reared by workers ofMyrmica laevinodis, at 22°C. An overwintering of both larvae ofAnergates and workers ofMyrmica is not necessary for the success of that experiment. The presence of larvae ofMyrmica does not keep theMyrmica from rearing larvae ofAnergates. The workers ofMyrmica have been cooled, in all the experiments, before receiving larvae ofAnergates. No queen ofMyrmica have been used in that experiments.38 of the 64 larvae ofAnergates used became imagos. Most of the 26 lostAnergates died at the beginning of the adoption and during the metamorphosis. The females lived generally 2 or 3 days and tried, very early, to leave their native nest. The males lived 2 or 3 weeks.

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Anergates atratulus Myrmica laevinodis, 22 . bmecme Anergates Myrmica. Myrmica Anergates. Myrmica Anergates. Myrmica . 64 Anergates , 38 . 26 Anergates 2 3 . 2 3 .

     

The effect of glycerol on the Chlorella symbiosis in Hydra viridis

In green hydra strains that are bleached by glycerol, photosynthesis is arrested in both intact hydra and freshly extracted algae whereas photosynthesis is not affected by glycerol in resistant hydra strains and their algae. Glycerol sensitivity is an inherent property of the algae and sensitivity can be transferred to resistant aposymbiotic hydra by infecting them with sensitive algae. It is suggested that the host hydra recognizes glycerol induced changes, other than photosynthetic incompetance, in the algae and either ejects or digests them.Australian Institute of Marine Science, P.M.B. No. 3, Townsville M.S.O. 4810 Australia     

Role of cyclic adenosine-3′,5′-monophosphate in olfactory reception

The action of cyclic adenosine-3,5-monophosphate (3,5-AMP) and of substances modifying the rate of its breakdown (inhibitors and activators of phosphodiesterase) on the olfactory epithelium was investigated in frogs. The slow electrical response of the olfactory epithelium to stimulation by solutions of various substances was recorded. Cyclic 3,5-AMP and its dibutyryl derivative were found to excite the olfactory receptors effectively. Responses to these substances developed after an appreciably longer delay than responses to stimulation by solutions of odiferous substances. It is postulated that the depolarizing action of 3,5-AMP and dibutyryl 3,5-AMP is manifested only after they have penetrated inside the receptor cell through its membrane. Both 5-AMP and cyclic 2,3-AMP were ineffective. In the next series of experiments the integral receptor potential was recorded in response to short stimulation by the vapor of an odiferous substance. The duration of this potential was increased after treatment of the olfactory epithelium with phosphodiesterase inhibitors: methylxanthines or papaverine. Conversely, the negative wave of the integral receptor potential was shortened under the influence of the phosphodiesterase activator imidazole. Cyclic 3,5-AMP is considered to play the role of mediator in the mechanism of excitation of the olfactory receptor; during interaction between an odiferous substance and the receptor, adenyl cyclase is activated and the concentration of 3,5-AMP increases; this, in turn, causes depolarization of the receptor cell membrane.Institute of Chemical Physics, Academy of Sciences of the USSR, Moscow. Translated from Neirofiziologiya, Vol. 5, No. 4, pp. 415–422, July–August, 1973.     

Differential expression of enzyme activities initiating anoxic metabolism of various aromatic compounds via benzoyl-CoA

The regulation of the expression of enzyme activities catalyzing initial reactions in the anoxic metabolism of various aromatic compounds was studied at the whole cell level in the denitrifying Pseudomonas strain K 172. The specific enzyme activities were determined after growth on six different aromatic substrates (phenol, 4-hydroxybenzoate, benzoate, p-cresol, phenylacetate, 4-hydroxyphenylacetate) all being proposed to be metabolized anaerobically via benzoyl-CoA. As a control cells were grown on acetate, or aerobically on benzoate. The expression of the following enzyme activities was determined.Phenol carboxylase, as studied by the isotope exchange between ¹⁴CO₂ and the carboxyl group of 4-hydroxybenzoate; 4-hydroxybenzoyl-CoA reductase (dehydroxylating); p-cresol methylhydroxylase; 4-hydroxybenzyl alcohol dehydrogenase; 4-hydroxybenzaldehyde dehydrogenase; coenzymeA ligases for the aromatic acids benzoate, 4-hydroxybenzoate, phenylacetate, and 4-hydroxyphenylacetate; phenylglyoxylate: acceptor oxidoreductase and 4-hydroxyphenylglyoxylate: acceptor oxidoreductase; aromatic alcohol and aldehyde dehydrogenases.The formation of most active enzymes is strictly regulated; they were only induced when required, the basic activities being almost zero. The observed whole cell regulation pattern supports the postulate that the enzyme activities play a role in anoxic aromatic metabolism and that the compounds are degraded via the following intermediates: Phenol 4-hydroxybenzoate 4-hydroxybenzoyl-CoA benzoyl-CoA; 4-hydroxybenzoate 4-hydroxybenzoyl-CoA benzoyl-CoA; benzoate benzoyl-CoA; p-cresol 4-hydroxybenzaldehyde 4-hydroxybenzoate 4-hydroxybenzoyl-CoA benzoyl-CoA; phenylacetate phenylacetyl-CoA phenylglyoxylate benzoyl-CoA plus CO₂; 4-hydroxyphenylacetate 4-hydroxyphenylacetyl-CoA 4-hydroxyphenylglyoxylate 4-hydroxybenzoyl-CoA plus CO₂ benzoyl-CoA.     

Full 1H NMR assignment of a 24-nucleotide RNA hairpin: Application of the 1H 3D-NOE/2QC experiment

The subject RNA models the binding site for the coat protein of the R17 virus, as well as the ribosome recognition sequence for the R17 replicase gene. With an RNA of this size, overlaps among the sugar protons complicate assignments of the ¹H NMR spectrum. The cross peaks that overlap significantly in 2D-NOE spectra can frequently be resolved by introducing a third, in our approach the double-quantum, frequency axis. In particular the planes in a 3D-NOE/2QC spectrum perpendicular to the 2Q axis are extremely useful, showing a highly informative repeating NOE-2Q pattern. In this experiment substantial J-coupling confers special advantages. This always occurs for geminal pairs (H5/H5 for RNA plus H2/H2 for DNA), as well as for H5/H6, for H3/H4 in sugars with substantial populations of the N-pucker, for H1/H2 for S-puckered sugars, and usually for H2/H3. For the 24-mer RNA hairpin the additional information from the 3D-NOE/2QC spectrum allowed assignment of all of the non-exchangeable protons, eliminating the need for stable-isotope labeling.     

Leaf thickness and carbon isotope composition in the Crassulaceae

Summary Measurements of leaf thickness and ¹³C value were obtained for twenty species and three intergeneric hybrids of the Crassulaceae. The data include plants growing in their native habitats and also in greenhouse cultivation. There is a strong relationship between leaf thickness and leaf ¹³C values. The plants with the thickest leaves of ca. 7 to 11 mm had ¹³C values ranging from -11.5 to -13.8. Plants with leaves that were thinner than 2.0 mm all had ¹³C values that were more negative than -23. Plants having intermediate leaf thickness possessed intermediate ¹³C values. The leaf tissue of four genotypes spanning the range of leaf thicknesses all exhibited a two-fold or greater nocturnal increase in titratable acidity. It appears that the differences in leaf thickness and ¹³C values among the tested species are genetically determined.     

Heritable variation in the phaseolin protein of nondomesticated common bean,Phaseolus vulgaris L.

Summary Crude protein extracts from single seeds of nondomesticated Mexican bean accessions were analysed by SDS polyacrylamide gel electrophoresis for variability in phaseolin protein. Six new phaseolin types; M1, M2, M3, M4, M5, M6, which contained polypeptides within the same range of molecular weights (51,000 to 45,000 daltons) as occur in the S, T and C phaseolin types of cultivated beans were identified. No T and C types were found among the non-domesticated Mexican accessions, and the S type occurred in less than 7% of the seeds screened. Genetic analyses of F₂ progenies from crosses between Sanilac (S), and five of the M types showed that each M phaseolin phenotype was allelic to the S type and expressed codominantly.     

Involvement of ABA in postharvest life of miniature potted roses

Exogenous application of ABA (abscisic acid) to intact miniature potted rose plants (Rosa hybrida L.) resulted in deterioration of postharvest quality of two cultivars. Spraying with ABA increased leaf drop and accelerated flower senescence in Vanilla and Bronze, while bud drop was only induced in Bronze. Application of ABA to detached rose flowers accelerated their senescence, indicating that the observed senescence promoting effect was not a secondary response resulting from ABA-induced leaf senescence and abscission. ABA-treatment increased ethylene production in Bronze flowers, while no ethylene production was measured in flowers of Vanilla, or in the leaves of both cultivars. Pre-treatment with 1-MCP (1-methylcyclopropene) delayed ABA promoted flower senescence in Bronze, suggesting that the effect of ABA is at least partly mediated by ethylene. The senescence promoting effect of ABA on leaf drop and flower life of Vanilla flowers was not counteracted by 1-MCP pre-treatment. The cultivar Vanilla had a low ABA level at all flower stages, while ABA content of the Bronze petals was high in buds, lower in open flowers, and increased during flower senescence. An increased ABA content after ethylene treatment in Vanilla suggests that ethylene, natural or exogenous, can increase ABA levels of flowers.     

Synthesis of aspartame precursor by solid thermolysin in organic solvent

Summary The enzymatic synthesis of a peptide compound was carried out successfully in homogeneous organic solvent.Solid Thermolysin was found to catalyze the synthetic reaction of N-benzyloxycarbonyl-L-aspartyl-L-phenylalanine methyl ester (Z-APM; a precursor of sweetner Aspartame) from N-benzyloxycarbonyl-L-aspartic acid (Z-L-Asp) and L-phenylalanine methyl ester (L-PheOMe) in a 98 percent organic medium (ethylacetatebenzenemethanolwater=5029192). The dissolution of enzyme was not observed. The optimal pH shifted to acidic side by 1.0 pH unit, compared with that in aqueous medium. The enzymatic activity of solid thermolysin with an average size of 3.4×9.5 m was determined to be 0.18 moles-product/(mg-solid)·h under the initial concentrations of L-PheOMe of 0.1M and Z-L-Asp of 0.05M, and at pH 6.0 and 40°C.     

The origin of Q-independent derivatives of phage lambda

Summary qsr (Q-independent) phages are characterised by the replacement of the region of the genome that contains Q, S, R, and the late gene promoter, P_R, with host-derived DNA that codes for functions analogous to those deleted. Restriction endonuclease analysis and DNA/DNA hybridisation methods have been used to show that p4 and qin A 3, two such Q-independent phages, are the product of recombination between and a defective lambdoid prophage (the qsr prophage) located at an as yet unidentified site in the E. coli K 12 chromosome. The qsr prophage is distinct from the defective lambdoid prophage Rac (Kaiser and Murray 1979). In the E. coli K 12 strain AB1157 from which qsr phages cannot be generated, the qsr prophage has suffered an internal deletion. That the qsr prophage appears not to carry a full complement of essential late genes suggests one explanation for its apparently defective nature.     

Determination of internal dynamics of deoxyriboses in the DNA hexamer d(CGTACG)2 by 1H NMR

The conformations and internal dynamics of the deoxyriboses of d(CGTACG)₂ have been determined by NMR measurements at 15°C. The conformations of the sugars were determined using coupling constants and time-dependent NOE measurements. The J-splitting patterns of the H1, H2 and H2 resonances show that the sugars exist as mixtures of conformations near C2 endo (south) and C3 endo (north). The population of the south conformation was larger for the purines than for the pyrimidines. The overall tumbling time of the molecule in ²H₂O was determined from measurements of the cross relaxation rate constant for the H6-H5 vectors of the two cytosine residues. Order parameters were determined for the H1-H2, H2-H2 and H2-H3 vectors from measurements of cross relaxation rate constants, making use of multi-spin analysis of the NOE build up rates. These order parameters are weakly dependent of the base sequence, and except for the terminal Cyt 1 residue, the H2-H2 and H2-H3 vectors are near unity, indicating the absence of rapid pseudorotation on the nanosecond time scale. However, the order parameter for the H1-H2 vector is significantly smaller than expected for rapid pseudorotation indicating the presence of other motions of the sugars. This motion must be about an effective axis parallel to the H2-H vector, and to occur with an angular fluctuation of about 30°.The results show that to obtain highly refined structures for nucleic acids by NMR the effects of spin diffusion and motional averaging cannot be ignored.Some of this work was presented as a poster at the 30^th Experimental NMR Conference at Asilomar, California 1989     

Effect of shape, size, and valency of multivalent mannosides on their binding properties to phytohemagglutinins

Clusters of di-, tri-, and tetra-antennary -D-mannopyranosides were synthesized in good yields based on the coupling of amine-bearing mono- or trisaccharide {Man (16)[Man (13)]Man} haptens to poly-isocyanate or -isothiocyanate tethering cores. The relative binding properties of the resulting multivalent ligands were determined by turbidimetric and solid phase enzyme-linked lectin assays (ELLA) using plant lectins (phytohemagglutinins) Concanavalin A (Con A) and Pisum sativum (pea lectin) having four and two carbohydrate binding sites, respectively. Rapid and efficient cross-linking between tetravalent Con A and mannopyranosylated clusters were measured by a microtiter plate version of turbidimetric analyses. In inhibition of binding of the lectins to yeast mannan, the best tetravalent monosaccharide (30) and trisaccharide (31) inhibitors were shown to be 140 and 1155 times more potent inhibitors than monomeric methyl -D-mannopyranoside against pea lectin and Con A, respectively. Compounds 30 and 31 were thus 35 and 289 fold more potent than the reference monosaccharide based on their hapten contents. As a general observation, the ligands bearing the Man (16)[Man (13)]Man trimannoside structures were found to be more potent inhibitors for Con A than the ligands having single mannoside residues, whereas pea lectin could not discriminate between the two types of ligands.     

Selective growth of a mutant in continuous culture of Bacillus caldolyticus for production of α-amylase

Summary In a continuous culture of Bacillus caldolyticus strain SP, which requires maltose as an inducer for production of -amylase in batch culture, a predominant mutant strain M1 which produced high amounts of -amylase in the absence of maltose in batch culture, developed. The change of cell population from strain SP to strain M1 in maltose-casitone medium was linear with time in the transient state after the change from batch to continuous culture at a dilution rate of 0.17 h^-1, and was completed in about 11 generations of bacterial growth. The dilution rate effect of continuous culture on -amylase activity was almost the same with both strains SP and M1. The maximum -amylase activity of 380 units/ml was observed at an intermediate dilution rate that was 11.5 times higher than -amylase activity at the end of a batch culture using the same medium. It was deduced that the enhancement of -amylase production in continuous culture was attributed partly to the predominant growth of a mutant strain with higher -amylase productivity.     

DNA markers tightly linked to a gall midge resistance gene (Gm2) are potentially useful for marker-aided selection in rice breeding

We have developed a polymerase chain reaction (PCR)-based assay that could effectively reduce the time period required to screen and select for Gall Midgeresistant rice lines under field conditions. The primers for the assay were designed on the basis of sequence information of two phenotype specific random amplified polymorphic DNA fragments which were found to be tightly linked to Gall Midge biotype-1 resistance gene (Gm2). The two RAPD fragments, F8₁₇₀₀ in the susceptible parent ARC6650 and F10₆₀₀ in the resistant parent Phalguna, were identified after screening 5450 loci using 520 random primers on genomic DNAs of ARC6650 and Phalguna. These primers, when used in a multiplexed PCR, amplified specifically a 1.7-kb and 0.6-kb fragment in the susceptible and resistant parents, respectively. When this assay was performed on genomic DNAs of 44 recombinant inbred lines derived from ARC6650 x Phalguna and 5 lines derived from other crosses where one of the parents was Phalguna, ARC6650 or their derivatives, the primers amplified a 1.7-kb fragment in all of the susceptible lines or a 0.6-kb fragment in all of the resistant ones. These markers can be of potential use in the marker-aided selection of Gall Midge biotype-1 resistant phenotypes. As screening for resistance can now be conducted independent of the availability of insects, the breeding of resistant varieties can be hastened.     

The energy transmission in ATP synthase: From the γ-c rotor to the α3β3 oligomer fixed by OSCP-b stator via the βDELSEED sequence

ATP synthase (F₀F₁) is driven by an electrochemical potential of H⁺ (H⁺). F₀F₁ is composed of an ion-conducting portion (F₀) and a catalytic portion (F₁). The subunit composition of F₁ is ₃₃. The active ₃₃ oligomer, characterized by X-ray crystallography, has been obtained only from thermnophilic F₁ (TF₁). We proposed in 1984 that ATP is released from the catalytic site (C site) by a conformational change induced by the DELSEED sequence via -F₀. In fact, cross-linking of DELSEED to stopped the ATP-driven rotation of in the center of ₃₃. The torque of the rotation is estimated to be 420 pN·å from the H⁺ and H⁺-current through F₀F₁. The angular velocity () of is the rate-limiting step, because H⁺ increased theV _max of H⁺ current through F₀, but not theK _m (ATP). The rotational unit of F₀ (=ab₂c₁₀) is /5, while that in ₃₃ is 2/3. This difference is overcome by an analog-digital conversion via elasticity around DELSEED with a threshold to release ATP. The distance at the C site is about 9.6 å (2,8-diN₃-ATP), and tight Mg-ATP binding in ₃₃ was shown by ESR. The rotational relaxation of TF₁ is too rapid (=100 nsec), but the rate of AT(D)P-induced conformational change of ₃₃ measured with a synchrotron is close to . The ATP bound between the P-loop and E188 is released by the shift of DELSEED from RGL. Considering the viscosity resistance and inertia of the free rotor (-c), there may be a stator containing OSCP (= of TF₁) and F₀-d to hold free rotation of ₃₃.     

Recognition sites for a membrane-derived DNA binding protein preparation in the E. coli replication origin

Summary The DNA binding protein B' preparation, isolated from the membrane of E. coli, recognizes two sites, one of which is locatd in the minimum oriC (35–270 bp) and the other between base pairs 417 and 488. Recognition is only possible when restriction fragments containing these sites are in single-stranded state. At the first site the strand reading 3OH-5P in the direction of the E. coli genetic map is recognized, at the second site the 5P-3OH strand.