Biosynthesis of 1-alkenes in the defensive secretions ofTribolium confusum (Tenebrionidae); stereochemical implications

Summary The terminally unsaturated hydrocarbons of the defensive secretion ofTribolium confusum are biosynthesized from fatty acids by oxidative decarboxylation. The process involves an enantiospecific cleavage of the C–H bond of thepro-(S) C(3)–H atom and simultaneous decarboxylation of the acid into an 1-alkene and carbon dioxide via ananti-periplanar transition state geometry (anti-elimination). The stereochemistry of this biotranformation is identical in all respects with the same reaction in higher plants. The mechanism seems to be of general importance for the biosynthesis of many vinylic substructures of natural products from oxygen-containing precursors.     

Cytotaxonomy of the myobatrachid frogs of the genusLimnodynastes

Summary 4 of the 5 species ofLimnodynastes of theperoni group show 2n=24. Onlysalmini has 2n=22, thus resembling the species ofPlatyplectron (thedorsalis andornatus complexes) which all show 22 chromosomes. This 2nd group also includes species (ornatus) with very low DNA amounts. From a karyological point of view, the species of thePlatyplectron (plus eventuallysalmini) group appear more differentiated than the species of theperoni group, from which they have probably arisen.Research partly supported by a contribution from C.N.R., Rome.     

Biochemical markers in the taxonomy of theActinomycetales

Summary Useful biochemical markers for the classification ofActinomycetales are: 1.dl-orll-diaminopimelic acid in the peptidoglycan, 2. sugar composition of polysaccharides, 3. fatty acid spectrum of cell lipids. The occurrence of various kinds of branched fatty acids and of unsaturated fatty acids is of special value.We should like to thank the Bundesministerium für Forschung und Technologie, Bonn, German Federal Republic, for the financial support of this project No. BCT 85.     

Resistance to ethidium bromide inAspergillus nidulans

Summary A mutant ofAspergillus nidulans resistant to ethidium bromide was isolated and the semi-dominant gene responsible for this resistance was allocated on linkage group II at 17.42±3.05 units of recombination from thewA₃ gene. The gene also confers cross-resistance to acriflavin, malachite green and crystal violet. It was also shown that riboflavin is antagonistic to the toxic effect of ethidium bromide, at certain concentrations. The mechanisms which could be responsible for the toxic effect of this drug are discussed and compared with those of acriflavin. The use of theEtb ₁ gene in genetical analysis through the parasexual cycle is suggested.Acknowledgements. The authors are thankful to the National Council for the Development of Science and Technology (CNPq) for financial support through PIG-SIP 04/053 FAPESP.     

Nest cell lining of the solitary beeHylaeus bisinuatus (Hymenoptera: Colletidae)

The nest cell lining ofHylaeus bisinuatus (Hymenoptera: Colletidae) was shown by high-resolution solidstate [¹³C]NMR to be composed of lipid polymer and protein. The lipid polymer was shown by reduction and subsequent GC/MS analysis to be comprised of -hydroxy fatty acids (C₂₀, C₂₂, C₂₄ and C₂₆) and fatty alcohols (C₁₆ to C₃₀). The protein portion of the lining had a silk-like amino acid composition.     

Mikrobiologische Spaltung razemischer Steroide. Synthese vond-Aldosteron

Summary A racemic intermediate in the total synthesis ofd, l-aldosterone, thed, l-20-oxo-pregnene derivative I, was converted by incubation with a mold hydroxylating in the 21-position into thed-20-oxo-21-hydroxy-pregnene derivative II, whereas thel-antipode of the starting material remained unchanged. This stereospecific microbiological reaction, comprising a separation of racemic modifications, represents the last remaining step in the synthesis of naturald-aldosterone.Other microbiological conversions of racemic steroids, dehydrogenation and hydrogenation, were also shown to proceed only with thed-enantiomer, leaving thel-form of thed, l-substrate intact.The advantages of this new microbiological method for the resolution of racemic modifications during the total synthesis of steroids are discussed.     

Thiamine-binding activity ofSaccharomyces cerevisiae plasma membrane

Summary The specific binding activity to [¹⁴C]thiamine was found to be located in the plasma membrane ofSaccharomyces cerevisiae. The activity was inhibited by several thiamine analogs and it was hardly detectable in the plasma membrane from a thiamine transport mutant ofSaccharomyces cerevisiae. Some properties of the thiamine-binding activity of yeast plasma membrane are discussed in connection with those of the thiamine transport system.     

Effect of various factors on the activity of trehalase from the larvae ofSesamia inferens walker (Insecta)

Summary Trehalase from the salivary glands and the midgut ofSesamia inferens showed optimum activity at pH 5.8, and at temperatures of 50 and 60°C respectively. The increase in the incubation period, enzyme concentration, and substrate concentration respectively increased the end-product, the hydrolysis, and the rate of hydrolysis of the substrate. Dialysis did not affect, tryptophan accelerated, and other amino acids and end-product inhibited the enzyme activity.The author wishes to express his thanks to ProfessorR. Rakshpal for his constructive criticism, and to University Grants Commission, India, for awarding a Junior Research Fellowship.     

Stimulation of sporulation by ppApp in a conditionally asporogenous rifampin-resistant mutant ofBacillus subtilis

Summary Addition of ppApp to Sterlini-Mandelstam medium stimulates sporulation of a conditionally asporogenous rifampin-resistant mutant ofBacillus subtilis to the same extent as the effect of 4 amino acids. Mutant cells sporulating in the presence of amino acids also produce 2 phosphorylated nucleotides one of which comigrated with ppApp on PEI thin layer chromatogram.Acknowledgment. This work was supported in part by a grant from Research Corporation, New York, New York.     

Growth ofNostoc muscorum mutants in the presence of diuron (DCMU) and L-methionine-DL-sulfoximine

Summary Diuron (DCMU) is inhibitory to the photoautotrophic and photoheterotrophic growth of the N₂-fixing blue-green algaNostoc muscorum at concentrations of 1.0×10^–5 M and 2.0×10^–5 M, respectively. A mutant of this organism resistant to 5.0×10^–5 M DCMU under its photoheterotrophic growth conditions, with the ability to utilize DCMU as a carbon and nitrogen source for growth, and complete inability to grow photoautotrophically has been isolated. With the apparent defect in its photosynthetic ability, it is suggested that theDCMU ^r mutant lacks the step inhibited by 1.0×10^–5 M DCMU, and metabolizes DCMU by an existing enzyme system in the absence of such inhibition. That this enzyme may be glutamine synthetase (GS) is explained with the help of a L-methionine-DL-sulfoximine (MSO)-resistant mutant ofN. muscorum which is able to grow faster with 2.0×10^–5 DCMU and is known to contain an altered GS.Thanks are due to the Council of Scientific and Industrial Research, CSIR Complex, Govt. of India, New Delhi-110012, for appointing the author to the Scientists' Pool for undertaking researches on the physiological and genetic controls of nitrogen metabolism in blue-green algae, a part of which is presented in this literature.     

Effect of exogenous application of nucleic acids and auxin on the rooting of hypocotyl cuttings ofImpatiens balsamina. Evidence for the uptake of information molecules

Summary Exogenously supplied DNA and RNA hastened root initiation and also increased the formation of roots on hypocotyl cuttings ofImpatients balsamina with intact apex and cotyledons. IAA appreciably increased the nucleic acid-caused enhancement in root formation. In combination with lowe concentrations of nucleic acids, it event stimulated the growth of roots as well as of hypocotyls. Higher concentrations of nucleic acids were, however, toxic.The research has been partly financed by a grant from the United States Department of Agriculture. One of us (SB) is thankful to the Deparmtent of Atomic Engery of the Government of India for financial assistance.     

Phylogenetic relationship of the Brasilian leptodactylid frog generaCraspedoglossa,Cycloramphus andZachaenus

Summary Based on immunological comparisons of the serum albumins ofCraspedoglossa andZachaenus with antisera to albumin of several species ofCycloramphus, it is concluded that morphological and biochemical evolutionary rates have not been comparable within the study group. Taken together, the morphological and biochemical information demonstrate that whileZachaenus is a genetic member of theCycloramphus lineage, it has attained generic status.This study was supported by NSF grant No. DEB78-23396, the Amazon Ecosystem Research Program, Smithsonian Institution, the Fluid Research Fund, Smithsonian Institution, and the Museu de Zoologia da Universidade de São Paulo.The authors gratefully acknowledge the following colleagues for their help in procuring frog samples: R.I. Crombie, M.C. Duchêne, F.I. McCullough, F.C. do Val and P.E. Vanzolini.     

Satellite DNA sequences and reproductive isolation in theDrosophila willistoni group

Summary Satellite DNAs of theDrosophila willistoni group have been analyzed by Hae III endonuclease digestion. Differences were observed between the 2 speciesD. willistoni andD. paulistorum and also between semispecies ofD. paulistorum and, to a lesser extent, between subspecies ofD. willistoni. Differences did not appear to be consistently greater between strains producing sterile hybrid males than between those producing fertile hybrids.This work was supported by grants 78.01852.65 from the CNR (Rome) and GM 22221 from the PHS (USA).     

Response ofHeliothis virescens to pheromonal components and an inhibitor in olfactometers

Summary Laboratory-reared males ofHeliothis virescens (F.) that were released in olfactometers in the laboratory were attracted to theH. virescens synthetic pheromone, but not to (Z)-9-tetradecen-1-ol formate (Z-9-TDF), or to either pheromonal component, (Z)-11-hexadecenal (Z-11-HDAL) or (Z)-9-tetradecenal (Z-9-TDAL). Also, they did not respond to the pheromone when it was dispersed simultaneously with Z-9-TDF. The proximity of the test chemicals in the olfactometer made little, if any, difference in the response ofH. virescens males to the pheromone source. Preexposure to the synthetic pheromone, Z-9-TDF, Z-11-HDAL, or Z-9-TDAL greatly reduced the number ofH. virescens males responding to the pheromone. This reduction was probably caused by habituation of the moths to these chemicals.The authors wish to thank A. H. Baumhover, E. Hart and other personnel of the Tobacco Research Laboratory, Oxford, N. C., for supplying many of the insects used in these studies.     

A reappraisal of the hormonal regulation of larval fat body histolysis in femaleDrosophila melanogaster

The histolysis of larval fat body cells in adult femaleDrosophila melanogaster was examined in wild type and mutant animals. The fat body cells of wild type (Canton-S),apterous ^56f homozygotes,apterous ^78jts homozygotes and heterozygotes,apterous ⁴/+, ecdysoneless¹ homozygotes and heterozygotes all underwent histolysis normally during the 72 h following adult eclosion. Only in the case ofap ⁴/ap⁴ adults did the cells fail to histolyze normally. The fat body cells of both diapausing and non-diapausing wild type females underwent histolysis at the same rate. Attempts to demonstrate histolysis in vitro were unsuccessful, even in the presence of juvenile hormones (JHs), larval ring glands, or adult ovaries. In all strains other than theap ⁴ homozygotes, a significant proportion of larval fat body cells were dead at any time while theap ⁴/ap⁴ animals, almost all cells remained viable. It is postulated that fat body cell lysis following eclosion is not a JH-mediated event, but is elicited by an as yet unidentified factor(s), possibly originating in the ovary.     

Unstable genetic system inDrosophila melanogaster: I. Instability at theCinnabar locus

Summary A mutant strain containing acinnabar allele (cn ^rbr ,rojo brillante) is reported, that produces wild-type revertants at thecinnabar (cn) locus. Incn ^rbr /cn heterozygotes the rate of mutation is highly increased. The presence of a mutator agent acting premeiotically is indicated.D.L. Lindsley and E.H. Grell, Genetic variations ofDrosophila melanogaster. Carnegie Institution of Washington, Washington, 1968; Publication No. 627.     

Negative phototaxis inDrosophila associated with a morphological change in the compound eye

Summary The ultrastructure of the compound eyes of several photonegative selection lines and their unselected photopositive controls of five species of themelanogaster subgroup was analyzed. A qualitative phenotypic change concerning the rhabdomeres in one of the photonegative selection lines ofD. mauritiana could be detected. It was proved that this structural aberration of the rhabdomeres is caused by a parallel mutation of the mutantora (outer rhabdomeres absent) ofD. melanogaster.     

Genetic variability ofApis mellifera ligustica Spin. in a marginal area of its geographical distribution

Summary Marginal populations ofApis mellifera ligustica differ from the central populations of this subspecies in allele frequencies at theMdh-1 locus. The difference seems to be due to gene flow from French populations ofA. m. mellifera.     

Organtypische und phasenspezifische Verteilung ungesättigter Lipoide im Schwanz der Larve vonXenopus laevis

Summary Barrollier's method for unsaturated fatty acids (u. f. a.) in paper chromatograms has been adapted for cytochemical detection of u. f. a. in the tails ofXenopus-larvae. A specific pattern in the different organs was found. It was further shown that the content in u. f. a. changes quickly, apparently indicating rapid changes in physiological conditions during growth and regeneration.     

Sclerotial and low aflatoxigenic morphological variants from haploid and diploidAspergillus parasiticus

Summary Serial transfer of mycelial macerates of a wild type, haploid, aflatoxigenic strain ofAspergillus parasiticus in a defined liquid medium resulted in the production of three new morphological classes: a sclerotial form with high aflatoxin production, and two variant forms (fan andfluff) with lowered sporulation, no sclerotia, and attenuated levels of aflatoxin. A genetically marked diploid containing mutant markers for aflatoxin pathway intermediates yielded the same three morphological classes upon serial transfer of macerated mycelia. When these diploid variants were treated with a haploidization agent, and the phenotypes of the resultant segregants scored, a low frequency of colonies producing aflatoxin pathway intermediates was recovered. These genetic data indicate that the structural genes for the aflatoxin pathway are present but somehow attenuated in thefan andfluff strains.This work was supported by a Cooperative Agreement from the U.S. Department of Agriculture, (58-7B30-3-556).