The F1 genes of the F1F0 ATP synthase from the acidophilic bacterium Thiobacillus ferrooxidans complement Escherichia coli F1unc mutants

Abstract Because of the allelic variations within the M protein gene ( emm gene) of group A streptococci, reliable typing of this important human pathogen can be accomplished by the use of emm gene-specific oligonucleotide probes. Two technical modifications (a reverse dot blot and a reverse line blot hybridization assay) of a novel approach for the type-specific identification of emm genes have been developed. Both procedures involved amplification of an emm gene by polymerase chain reaction. The non-radioactively labeled amplicon was subsequently hybridized to a membrane carrying an array of immobilized emm gene-specific oligonucleotide probes, thus allowing the simultaneous analysis of the gene polymorphism in a single hybridization reaction. The feasibility of these rapid and easy to perform methods was shown for the unequivocal identification of reference strains and clinical isolates belonging to 16 different M serotypes.     

Factors affecting field-scale production of seed of F1 hybrid Brussels sprouts

The two main factors involved in field-scale production of seed of F₁ hybrid Brussels sprouts are pollen availability and honeybee behaviour. Pollen availability depends upon the extent of winter survival of the parent inbreds, their flowering times, plant size and on the number of flowers per plant. Plant losses varied between inbreds and between sites and seasons. Differences in the commencement of flowering time in pairs of inbreds varied from 7 to 21 days, and plant size affected flower number. In hybrid seed-production there was a direct relationship between the number of mature flowers on each inbred and the percentage of non-hybrid seed produced from that inbred. Bees were highly selective in their visits to inbreds, and a mean selfing-to crossing-movement ratio of 30:1 was observed. This behaviour, together with pollen availability, greatly influenced the production of ‘sibs’. Radioactive experiments showed that the amount of cross-pollen carried by a bee decreased by about 30% at each flower visited but radioactive pollen grains were detected on the tenth flower visited. Of a number of factors investigated as possibly influencing bee behaviour, differences in flower colour and plant height were associated with discrimination between inbred lines.     

Acid phosphatase isoenzymes of Brassica oleracea seedlings and their application to sib testing in F1 hybrids

Crude extracts from cotyledons of 2-day-old seedlings were separated by electrophoresis on polyacrylamide gels and stained for acid phosphatase. At least 22 bands were recognised, distributed over seven zones. Analysis of zone 1 allowed estimation of sib frequencies in 12 out of 19 hybrid cultivars. By applying either seedling zone 1 or acp-1 seed acid phosphatase analysis, sib estimates could be made in 15 of these hybrids. It is suggested that this technique offers a practical and rapid means of estimating sib frequencies in commercial seed stocks.     

Inheritance of Pathogenicity of Progeny from an F1 Culture of Melampsora lini

Abstract Races 1 and 400 of Melampsosau bni the causal agent of flax [Lmum usitatissimum]), were crossed and the resulting F² progeny evaluated on near-isogcnic fiax lines. The infection type of the parental cultures, the F¹² and the segregating f² progeny were used to evaluate the inheritance of pathogenicity. Races 1 and 400 as well as the F² and all the F² progeny were avirulent on lines N and P⁴ genes. This indicated both races to be homozygous avirulent. The F² and all the F² progeny were virulent on lines containing L9, M1, M4, and P. This indicated the F to be homuzygous for virulence at these loci. Segregation ratios of the F² cultures fit monogenic ratios on lines with host genes K. L2, L5, L6, L7, L11, M, M2, M3, N1, P1, P2, and P3. Race 1 was avirulent, race 400 virulent and tht F, avirulent on these lines. Several linkage groups were indicated including close linkage at A^p1, A^p2 and A^p3. Segregation on lines L, L3, M5, M6 and cultivars Flor, Dufferin, Linott, and Wishek fit a digenic model. The infection tvpes of the parents, the F¹ and the F², segregations could usually be explained by classical gene-for-gene interactions. Possible exceptions were segregations on L4, L8 and N2 which did not fit a 3: 1 ratio but did fit a 9: 7 ratio. Segregation on L 10 fit a 7: 9 ratio but line L10 may be temperature sensitive. Segregation on L1 indicated a single dominant gene for pathogenicity.     

The feasibility of producing inbred rather than F1 hybrid cultivars in Brussels sprouts: predictions from early generations

Predicting the performance of recombinant inbred lines derived by single seed descent (SSD) following crosses between inbred lines is most reliable for traits in which epistasis and genotype environment interaction are absent. The analysis of two field trials of Brussels sprouts indicated the presence of such effects in seven quantitative characters. These effects could be minimised by transforming the scale on which each character was measured. Predictions were made of the likely performance of the recombinant inbred lines currently being produced by SSD at the Institute of Horticultural Research, Wellesbourne, compared with that of current F₁ hybrid varieties. The predictions from the first trial of F₂ material were encouraging for harvest date, stem length and waste weight, but low for sprout number, quality, marketable yield and total yield. Predictions from F₃ material in the second trial were good for sprout number and total yield (in addition to harvest date, stem length and waste weight as before), but still low for marketable yield and quality, with less than 0 01% of lines expected to perform better than the F₁. Model fitting to variances suggested the presence of linkage disequilibrium in dispersion for waste weight, but no information could be obtained about linkage disequilibrium for the two most important characters, marketable yield and quality. The broad heritability of each character except stem length was lower than 0 5 (0 3 or lower for total yield, waste weight and quality), suggesting that advanced generation selection, as used in SSD, might be more successful than selection in the early generations.     

Chloroplast ultrastructure in two Crassulacean species and an F1 hybrid with differing biomass δ13C values

Abstract. The chloroplasts of two species of the Crassulaceae and their F₁ hybrid were compared by electron microscopy. The two species had contrasting leaf tissue δ¹³C values of −25°/_∞ ( Sedum greggii ) and −13°/_∞ ( Cremnophila linguifolia ), and the F₁ hybrid had a value of − 18°/_∞. S. greggii had a mean of 8.9 thylakoids per granum in contrast to C. linguifolia which had a mean of only 3.8 thylakoids per granum. The F₁ hybrid had a mean of 6.4 thylakoids per granum. Crystaloids were observed in S. greggii and the hybrid but not in C. linguifolia     

Predictors of marker-informativeness for an outbred F2 design

Generalization of the polymorphism information content (PIC) index to represent marker informativeness (MI) for a three-generation F2 design requires that two additional sources of non-informativeness be added to the PIC formula: the probability of matings between like-heterozygous F1 individuals, of which one is non-informative; and that of matings between like-heterozygous F1 individuals, which are both fully informative but where line of origin of the same alleles is reciprocal. Given the dense marker-maps currently available for some species, this F2 informativeness parameter constitutes the natural criterion for marker selection in F2 designs, and two computer programs to predict MI from grandparental marker-genotypes were developed for an F2 population originating from two divergent selection lines of outbred mice (F approximately 0.2). A total of 403 markers had been genotyped for the F0 grandparents (n=31), and 14 markers had also been genotyped in the complete pedigree including 559 F2 individuals. One program was based on assumptions of random-mating (RM), while the other (PED) accounted for the pedigreed mating structure. For the 403 markers, the correlation between MI from RM and from PED was 0.95, and the average deviation between the two predictions was 0.005 MI units (MI ranged from 0 to 1). Correlations between predicted and realized MI for the 14 fully genotyped markers were 0.97 for PED and 0.94 for RM, while the corresponding average of deviations between predicted and actual values were 0.01 and 0.04, respectively. Absolute deviations from realized MI never exceeded 0.09 and 0.16 for PED and RM, respectively. Simulated optimization of the mating system to maximize average MI of 28 markers on one chromosome led to improvements in the range of 15-20% average MI (0.07-0.09 MI units). The degree of relative advantage conferred by the F2 generalization of the PIC index over the traditional index was found to be of minor significance.     

Some expression of heterosis in F1-hybrid barley

Small and large scale trials of F₁ barley hybrids were done in a glasshouse in the United Kingdom and in the field in the United Kingdom and Europe in 1970, 1971 and 1972. The results showed that there were few instances of significant positive heterosis in yield with either the small or field scale experiments. The hybrids studied were all derived from American varieties as male-sterile parents and therefore the hybrids were not adapted to European countries, thus the case for or against F₁-hybrids cannot be assessed solely on this material.     

Matching inbred lines of Brussels sprouts for flowering characteristics, as an aid to improving F1 hybrid seed production

Previous work at the National Vegetable Research Station indicated that cross-pollination of Brussels sprouts by honeybees could be improved when parent lines with similar flowering characteristics were used. During 1973-5 inbred lines were tested at three sites for matching ability based on flowering times, plant height and flower colour. One pair of inbreds satisfied all criteria at all sites, and a further twelve gave satisfactory results. Two pairs visually matched in 1973 were grown in larger plots in 1973-4 to assess the effect of matching on honeybee behaviour. Results showed that matching improved cross-pollination by honeybees between the parent lines.     

Effect of plant density and nitrogen on wheat F1 hybrids and their parents

The autonomous spread of Gaeumannomyces graminis var. tritici from discrete sources of inoculum, consisting of naturally infected stubble and roots, was measured in three field experiments. Spread occurred from only half of the inoculum sources and when it did occur it averaged a distance of only 10 cm.     

Regional Distribution of Prostaglandins D2, E2, and F2α and Related Enzymes in Postmortem Human Brain

Abstract: The presence of prostaglandins D₂, E₂, and F_2α was demonstrated and their contents measured in various regions of postmortem human brain, pineal body, and pituitary by using specific radioimmunoassays and gas chromatography-mass spectrometry. The three prostaglandins were widely distributed in similar concentrations ranging from several hundred pg/g wet weight to about 40 ng/g wet weight. Prostaglandins D₂ and E₂ showed consistent and similar regional distributions in all six brains tested; amounts were high in pineal body, pituitary, olfactory bulb, and hypothalamus. On the other hand, prostaglandin F_2α was distributed more evenly. Prosta- glandin D synthetase and prostaglandin E synthetase activities were found in cerebrum homogenate from a single subject and were recovered from the 100,000 × g supernatant. The presence of 1 m M glutathione, reduced form, markedly stimulated the activity of prostaglandin E synthetase, but did not affect prostaglandin D synthetase activity. Activity of 15-hydroxyprostaglandin dehydrogenase was found in the cerebrum homogenate and was partially purified. This enzyme required NADP as a cofactor and copurified with prostaglandin E 9-ketoreductase.     

A Chemical Indicator for the Rapid Measurement of F0 Values

A new chemical indicator for monitoring steam sterilization processes has been calibrated in F ₀ units. The effective temperature range for F ₀ measurements using this device has been shown to lay between 115 and 123°C. The effective F ₀ range of the device has been shown to be 4–23 F ₀ units. Using the device, measurements can be made within 0.5 units of conventionally calculated F ₀ values.     

Environmental and genetic control of crassulacean acid metabolism in two crassulacean species and an F1 hybrid with differing biomass δ13C values

Abstract The growth, biomass δ¹³C values, and ability to accumulate titratable acidity at night were compared in eight environmental treatments for Cremnophila linguifolia, Sedum greggii, and their F₁ hybrid. In the phytotron, differences in treatment daylength, day/night temperature and water availability were all found to have effects on total plant dry weight, nocturnal accumulation of titratable acidity and biomass δ¹³C value of at least some of the genotypes. However, there were differences between the genotypes both in the magnitude and direction of response of the phenotypic properties to the treatment variables. The phytotron δ¹³C values ranged from -12.9 to -19.2‰ for C. linguifolia, from -22.2 to -33.4‰ for S. greggii, and from -19.2 to -24.9‰ for the hybrid. After with-holding water for 76 h both C. linguifolia and the hybrid had midday Ψ_leaf values of -0.23 MPa; however, S. greggii had a value of -1.05 MPa. In contrast to past observations of other species, the daily watered plants of C. linguifolia had less negative δ¹³C values than did the plants watered only weekly.     

The F1FO ATP synthase genes in Methanosarcina acetivorans are dispensable for growth and ATP synthesis

There is a long-standing discussion in the literature, based on biochemical and genomic data, whether some archaeal species may have two structurally and functionally distinct ATP synthases in one cell: the archaeal A₁A_O together with the bacterial F₁F_O ATP synthase. To address a potential role of the bacterial F₁F_O ATP synthase, we have exchanged the F₁F_O ATPase gene cluster in Methanosarcina acetivorans against a puromycin resistance cassette. Interestingly, the mutant was able to grow with no difference in growth kinetics to the wild type, and cellular ATP contents were identical in the wild type and the mutant. These data demonstrate that the F₁F_O ATP synthase is dispensable for the growth of M. acetivorans .     

Hybridisation in the genera Vulpia and Festuca: the production of artificial F1 plants

The results of hybridisation experiments involving 24 strains of diploid, tetraploid and hexaploid Vulpia , representing nine species in three sections, and 22 strains of hexaploid and octoploid Festuca rubra agg., are presented, and the taxonomic implications discussed. 7848 pollinations produced 741 hybrid caryopses, from which 137 mature hybrid plants were raised (1.75% success rate) by embryo culture. Festuca x Festuca crosses were relatively easily achieved, and Festuca x Vulpia crosses were as successful as Vulpia x Vulpia crosses, indicating a close relationship between these two genera. Hybrids with F. rubra agg. were raised from females of species from all three sections of Vulpia. Within Vulpia , the most successful crosses involved V. geniculata, V. ligustica, V. fasciculata and V. pyramidata , whereas V. alopecuros was the least successful parent of all, producing only one mature hybrid from 2595 pollinations.     

Electrophoretic analysis of protein systems of Ctenopharyngodon idella (Val.), Hypophthalmichthys nobilis (Rich.) and their F1 triploid hybrid

Electrophoretic analysis was performed on eight protein systems (lactate dehydrogenase, liver esterases, superoxide dismutase, haemoglobin, isocitrate dehydrogenase, glucose-6-phosphate dehydrogenase, 6-phosphogIuconate dehydrogenase, transferrin) in Ctenopharyngodon idella, Hypophthalmichthys nobilis , and their F₁ triploid hybrid. The data demonstrated codominant Mendelian inheritance at individual loci for each protein system. Transferrin and superoxide dismutase were the only proteins found to be polymorphic in either parental species. Both parental alleles were present and functional at each enzyme locus examined in the F₁ triploid hybrid.     

CATABOLISM OF PROSTAGLANDIN ENDOPEROXIDES INTO PROSTAGLANDIN E2 AND F2x BY THE RAT BRAIN

Abstract— Tritium labeled prostaglandin (PG) endoperoxides PGG₂ and PGH₂ were rapidly transformed (2 min, 37°C) in good yield (> 50%) by homogenates of whole rat brain into a mixture of products including prostaglandin E₂ and F_2x: under similar conditions (10min. 37°C) tritium labeled arachidonic acid remained essentially unoxidised. The ratio of PGE-like products: PGF_2x formed was approx 0.5 as determined by radio thin layer chromatography. This ratio changed to unity when homogenates of cerebral cortex or cerebral hemispheres were employed. On the other hand cerebellar homogenates formed PGF_2x in much greater amounts. The structures of the products were confirmed by mass spectrometry and were further supported by experiments using octadeuterio-endoperoxides. In the latter experiments the resulting PGE₂ and PGF_2x contained the expected seven and eight deuterium atoms respectively. Evidence for the formation of heptadeuterio PGD₂. heptadeuterio-6-keto-PGF₁, and hexadeuterio 12-hydroxyheptadecatrienoic acid was also obtained by mass spectrometry. These experiments demonstrate for the first time in brain tissue the biosynthesis of labeled prostaglandins from exogenous tritiated and deuterated precursors.