DNA Distribution in Spermatid Nuclei of Normal and Segregation Distorter Males of DROSOPHILA MELANOGASTER

Using the DNA-specific dye BAO [2,5-bis-(4'-aminophenyl-(1')]-1,3,4-oxadiazol), we have examined spermiogenesis in wild-type males of Drosophila melanogaster and in males carrying various combinations of the Sd and Rsp mutations involved in segregation distortion. Wild-type strains, even those newly collected from nature, are heterogeneous with respect to the incidence of spermiogenic abnormalities, principally in having a variable number of spermatid nuclei per cyst that fail to undergo complete elongation. Among segregation distorter males, Rsp/Rsp homozygotes have the greatest incidence of nuclear nonelongation or incomplete elongation, Rsp/Rsp ⁺ heterozygotes are intermediate, while Rsp⁺/ Rsp⁺ homozygotes have the least amount of abnormality. Indeed, Sd Rsp⁺/Sd⁺Rsp⁺ males have significantly fewer spermiogenic aberrations than do wild-type strains.     

Asymmetric crossing over in the spontaneous formation of large deletions in the tonB-trp region of the Escherichia coli K-12 chromosome

The chromosomal tonB gene of Escherichia coli was used as a target for the detection of spontaneous deletion mutations. The deletions were isolated in both recA ⁺ and recA ^? cells, and mutants carrying large deletions were identified because they also lacked part or all of the trp operon. The frequencies of tonB-trp deletion were 1.79?×?10^?9 and 1.09?×?10^?9 for recA ⁺ and recA ^? cells, respectively. We analyzed 12 deletions from recA ⁺ and 10 from recA ^? cells by cloning and direct sequencing. The deletions ranged in size from 5612?bp to 15142?bp for recA ⁺ and from 5428?bp to 13289 for recA ^? cells. Three deletions from recA ⁺ cells and five deletions from recA ^? cells were found to have occurred between short sequence repeats at the termini of the deletion, leaving one copy of the repeat in the mutant sequence. Seven deletions from recA ⁺ cells and three deletions from recA ^? cells did not have repeats at their termini; in these cases, the DNA sequences that are adjacent to the deletion termini in the wild-type are characterized by short (2–4?bp) repeats. From these results, a model is presented for the generation of deletion mutations which involves formation of an asymmetric crossover mediated by repeated sequences of 2- to 4-bp.     

Changes in the mechanical properties of the extensible cuticle of Rhodnius through the fifth larval instar

The ultimate tensile strength (σ_UT) and the modulus of elasticity (E) of Rhodnius extensible cuticle are σ_UT = 2.20 × 10⁷ Nm^?2, E = 2.43 × 10⁸ Nm^?2 (unplasticised); σ_UT = 1.43 × 10⁷ Nm^?2, E = 9.45 × 10⁶ Nm^?2 (plasticised with 5HT) and σ_UT = 9.05 × 10⁶ Nm, E = 2.46 × 10⁶ Nm^?2 (plasticised in pH 5 buffer).The mechanical properties of cuticle from insects which have deposited additional layers of cuticle after they have been fed differ from those of cuticle from unfed insects. This is possibly due to the different composition of the additional cuticle: it is suggested that the post-feeding cuticle is providing protection and a template for the next instars cuticle.The maximum strain of extensible cuticle from starved insects is related to the amount of matrix protein present.     

Synthesis of P 1-(11-phenoxyundecyl)-P 2-(��-D-galactopyranosyl) diphosphate and P 1-(11-phenoxyundecyl)-P 2-(��-D-glucopyranosyl) diphosphate and investigation on their acceptor properties in the reaction of mannosyl residue transfer catalyzed by mannosyltransferase from Salmonella newport

P ¹-(11-phenoxyundecyl)-P ²-(??-D-galactopyranosyl) diphosphate and P ¹-(11-phenoxyundecyl)-P ²-(??-D-glucopyranosyl) diphosphate have been synthesized for the first time, and their ability to serve as a mannosyl residue substrate-acceptors in the enzymatic reaction, catalyzed by mannosyltransferase membrane preparation from Salmonella newport cells, was investigated. It was demonstrated that the derivative containing galactopyranose residue is able to accept the mannosyl residue from GDP-Man, while the derivative containing glucopyranose residue does not have such an ability.     

Flash photolysis-electron spin resonance study of the effect of o-phenanthroline and temperature on the decay time of the ESR signal B1 in reaction-center preparations and chromatophores of mutant and wild strains of Rhodopseudomonas spheroides and Rhodospirillum rubrum

We have studied the effect of o-phenanthroline and temperature on the decay rate of Signal B1 in reaction-center preparations and in chromatophores from Rhodopseudomonas spheroides and Rhodospirillum rubrum. We have shown that o-phenanthroline binds specifically to the reaction center protein (the binding center is probably at the iron) and when so bound inhibits the transfer of electrons from primary to secondary acceptors. We have also shown that the direct return decay time (A^? → P865⁺) increases with increasing temperature above approx. 150 K. This phenomenon has been interpreted within a quantum mechanical tunnelling model in which the distance of closest approach between P865⁺ and A^? increases about 2 Å between approx. 150 and 300 K.     

Oxygen equilibria of hemoglobin A and hemoglobin S valency hybrids.

Oxygen equilibrium determinations with “unsymmetrical” MetHb/Hb hybrids derived from human hemoglobins A and S are reported. All four of the possible hybrids have higher oxygen affinity than the parent hemoglobins. The α₂^Metβ₂^S hybrid has a lower oxygen affinity than that of α₂^Metβ₂^S. However, both the β^Met hybrids have similar oxygen affinity. The Bohr value of α₂^Metβ₂^S is more negative than that of α₂^Metβ₂^A while the β^Met hybrids appear to have almost identical Bohr values. These findings favor the view that α and β chains in hemoglobin A have different conformations and indicate that hemoglobin S has a β-chain conformation different from that of β-chain of hemoglobin A. This difference is probably carried into the oxygenation properties of the α-chain in such a way as to be reflected only when the β chain is oxidized.     

Substrate stereochemistry of isovaleryl-CoA dehydrogenase elimination of the 2-pro-R hydrogen in biotin-deficient rats

(2R)-[³H]Isovaleric acid and (2S)-[³H]isovaleric acid (ammonium salts) have been synthesized. These substances, mixed with [1-¹⁴C]isovalerate, have been administered to biotin-deficient rats, which accumulate β-hydroxyisovaleric acid in their urine, the metabolite being formed via isovaleryl-CoA and β-methylcrotonyl-CoA. The results show that most of the tritium from (2R)-[³H]isovalerate was lost, and most of the tritium from (2S)-[³H]isovalerate retained in the conversion to β-hydroxyisovalerate. The stereochemistry of the isovaleryl-CoA dehydrogenase reaction is compared with the stereochemistry of other short-chain acyl-CoA dehydrogenase reactions.     

Phototropism mutants of Phycomyces blakesleeanus isolated at low light intensity

Mutants of Phycomyces have played a major role in the analysis of phototropism and other responses. Fifteen new mutants of Phycomyces with abnormal phototropism (genotype mad) have been isolated on the basis of their inability to bend toward dim unilateral blue light (fluence rate 5 × 10⁻⁷ W m⁻²), a protocol different from those employed in previous mutant hunts. One mutant resulted from chemical mutagenesis with ICR-170, and the other 14 were induced with N-methyl-N′-nitro-N-nitro-soguanidine. Seven of the mutants are “night blind”; six have phototropic thresholds intermediate between those of wild type (10⁻⁹ W m⁻²) and madA strains (∼ 10⁻⁴ W m⁻²); and one has a threshold similar to that of night-blind madB and madC mutants. The other eight mutants are “stiff”, with various reductions of tropic responsiveness. Two of them, when compared to previously isolated stiff mutants, show unusually weak responses to light, barriers, and gravity.     

Deuterium isotope effects in carbohydrates revisited. Cryoprobe studies of the anomerization and NH to ND deuterium isotope induced 13C NMR chemical shifts of acetamidodeoxy and aminodeoxy sugars

Complete ¹H and ¹³C NMR chemical shift assignments have been generated from a series of acetamidodeoxy and aminodeoxy sugar derivatives. For free sugars, the enhanced sensitivity of an NMR cryoprobe allowed simple 1D and 2D NMR spectra to be obtained from essentially single anomers, before significant mutarotation had occurred. The NMR assignments have been used to characterize deuterium isotope effects on ¹³C chemical shifts measured under conditions of slow NH to ND exchange in single solutions. Within a range of 0 to −0.138 ppm, β, γ, δ, and ζ deuterium isotope effects have been observed, thus providing additional reference data for assignment of the ¹³C NMR spectra of nitrogenous saccharides.     

Reconstitution of the R compound allele in maize

The R^r:standard allele in maize, which conditions anthocyanin pigmentation in plant and seed tissues in the presence of appropriate complementary factors, is associated with a tandem duplication. The proximal member of the duplication carries P, the plant pigmenting determiner and the distal member member carries S, the seed pigmenting determiner. Derivatives from R^r that have lost S function are designated r^r. They represent either losses of the distal member of the duplication (P derivatives) or mutations of S to s (P s). Derivatives that have lost P function are designated R^g, and represent either losses of the proximal member of the duplication (S derivatives) or mutations of P to p (p S).—All four possible types of r^r/R^g heterozygotes were tested for their capacity to yield R^r reconstitution by crossing over. No R^r derivatives were obtained from P/S heterozygotes, a result consistent with the view that P and S occupy corresponding positions in homologous chromosome segments. R^r reconstitution was detected in both tandem duplication heterozygotes P s/S and P/p S, and was found to be about ten times more frequent in the latter. The ratio of R^r reconstitution in the two heterozygotes is a function of position of the anthocyanin marker within the duplicated segment. The data from these heterozygotes allow one to measure the distance between P and S, that is to say, the genetic length of the duplicated segment. This distance was found to be 0.16 map units. The highest frequency of R^r reconstitution was obtained from P s/p S heterozygotes, since direct pairing (see PDF) as well as the p//s type of displaced pairing have the potential to produce R^r derivatives. One of the R^g derivatives used in this study, R^g₆, was found to back-mutate in some sublines to R^r. The basis for this instability remains unknown.     

Genetic Analysis of Petite Mutants of SACCHAROMYCES CEREVISIAE : Transmissional Types

We have studied a number of petite [rho^- ] mutants of Saccharomyces cerevisiae induced in a wild-type strain of mitochondrial genotype [ome^- CHL ^R ERY^S OLI^S_1,2,3 PAR^S] by Berenil and ethidium bromide, all of which have retained two mitochondrial genetic markers, [CHL^R] and [ERY^S], but have lost all other known markers. Though stable in their ability to retain these markers in their genome, these mutants vary widely among themselves in suppressiveness and in the extent to which the markers are transmitted on crossing to a common wild-type tested strain. In appropriate crosses all of the strains examined in this study demonstrate mitochondrial polarity, and thus have also retained the [ome^-] locus in a functional form; however, five different transmissional types were obtained, several of them quite unusual, particularly among the strains originally induced by Berenil. One of the most interesting types is the one that appears to reverse the parental genotypes with [CHL^R ERY^S] predominating over [CHL^S ERY^R] in the diploid [rho+] progeny, rather than the reverse, which is characteristic of analogous crosses with [rho+] or other petites. Mutants in this class also exhibited low or no suppressiveness. Since all of the petites reported here are derived from the same wild-type parent, and so have the same nuclear background, we have interpreted the transmissional differences as being due to different intramolecular arrangements of largely common retained sequences.     

Electrophoretic behavior of oligonucleotides containing 5-hydroxymethyl cytosine

³²P-labeled oligonucleotides from a pancreatic DNase digest of non-glucosylated T2 gt^? DNA have been analyzed by high voltage electrophoresis (both before and after dephosphorylation of the 5′ terminus). T2 gt^? oligonucleotides, which contain 5-hydroxymethyl cytosine (hm⁵C) in place of cytosine (C), have altered electrophoretic mobilities compared to fd DNA oligonucleotides (which contain C). In addition, we have observed that pancreatic DNase exhibits a marked cleavage specificity; i.e., hm⁵C is the predominant 5′ terminal residue in the hm⁵C-containing oligonucleotides we have characterized.     

Physical and genetic organization of Petite and Grande yeast mitochondrial DNA. II. DNA-DNA hybridization studies and buoyant density determinations

Buoyant density of mitochondrial DNA from 14 cytoplasmic petite mutants issued from the same grande yeast Saccharomyces cerevisiae was determined. Mutants that have retained the mitochondrial gene conferring resistance to erythromycin displayed higher buoyant density, while mutants that have retained the mitochondrial gene conferring resistance to chloramphenicol displayed lower buoyant density. It is inferred that the segment which carries the E^R gene has a higher G + C content than the segment which carries the C^R gene. DNA-DNA filter hybridizations were carried out systematically in different reciprocal pair-wise combinations between mtDNAs purified from various mutants and from the grande. All petites were found to be deleted in 42 to 93% of the grande sequence, depending on the mutant studied. Sequence homology between petite mtDNAs was greatest in mutants retaining common genetic markers and was least when different genetic markers were retained. Practically no hybridization was found between some C^RE^O and C^OE^R mutants. Correlations established between the extent of DNA-DNA hybridization, kinetic and genetic complexity show that a selective enrichment of gene specific sequences occurs in mtDNA of petites.     

Sapogenins of Yucca glauca seed pods

From the fruiting pods of Yucca glauca Nutt. devoid of seeds the following sapogenins have been isolated and identified: neo-tigogenin, hecogenin, gitogenin, manogenin, Δ⁹-manogenin and sarsasapogenin. A small amount of a material believed to be Δ²-desoxysarsasapogenin was also isolated and is apparently an artifact arising from the hydrolysis and extraction procedure. Manogenin and Δ⁹-manogenin have not been previously detected in Y. glauca, and Δ⁹-manogenin has not been reported in any Yucca species.     

Isopentenyladenine from mutants of the moss, Physcomitrella patens

The culture media from gametophore over-producing mutants of the moss Physcomitrella patens have been examined for their cytokinin content. Two cytokinins have been detected, one of which has been identified as N⁶-(Δ²-isopentenyl) adenine (2iP).     

Mobilization of the gypsy and copia retrotransposons in Drosophila melanogaster induces reversion of the ovo dominant female-sterile mutations: molecular analysis of revertant alleles

The ovo locus is required for the maintenance of the female germ line in Drosophila melanogaster. In the absence of an ovo⁺ gene, males are completely normal but females have no germ-line stem cells. Three dominant mutations at the ovo locus, called ovo^D, were observed to revert towards recessive alleles at high frequency when ovo^D males were crossed to females of the strain y v f mal. We have found that this strain contains an inordinately high number of gypsy transposable elements, and crossing it with the ovo^D strains results in the mobilization of both gypsy and copia, with high-frequency insertions into the ovo locus: of 16 revertants examined 12 have gypsy and four have copia inserted at 4E, the ovo cytological site. Using gypsy DNA as a tag we have cloned 32 kb of wild-type DNA sequences surrounding a gypsy insertion and characterized molecular rearrangements in several independent revertants: in 10 of them gypsy appears to be inserted into the same site. The orientation of gypsy is strictly correlated with whether the neighbouring lozenge-like mutation appears in the revertants. A distal limit of the ovo locus was molecularly determined from the breakpoint of a deletion affecting closely flanking regions.     

A fish bradykinin (Arg0, Trp5, Leu8-bradykinin) from the defensive skin secretion of the European edible frog, Pelophylax kl. esculentus: structural characterization; molecular cloning of skin kininogen cDNA and pharmacological effects on mammalian smooth muscle

Extensive studies on bradykinin-related peptides (BRPs) generated from plasma kininogens in representative species of various vertebrate taxa, have confirmed that many amphibian skin BRPs reflect those present in putative vertebrate predators. For example, the (Val¹, Thr⁶)-bradykinin, present in the defensive skin secretions of many ranids and phyllomedusines, can be generated from plasma kininogens in colubrid snakes—common predators of these frogs. Here, we report the presence of (Arg⁰, Trp⁵, Leu⁸)-bradykinin in the skin secretion of the European edible frog, Pelophylax kl. esculentus, and have found it to be encoded in single copy by a kininogen with an open-reading frame of 68 amino acid residues. This peptide is the archetypal bony fish bradykinin that has been generated from plasma kininogens of the bowfin (Amia calva), the long-nosed gar (Lepisosteus oseus) and the rainbow trout (Onchorhynchus mykiss). More recently, this peptide has been shown to be encoded within cloned kininogens of the Atlantic cod (Gadus morhua) spotted wolf-fish (Anarichas minor), zebrafish (Danio rerio), pufferfish (Tetraodon nigroviridis) and Northern pike (Esox lucius). The latter species is regarded as a major predator of P. kl. esculentus. Synthetic (Arg⁰, Trp⁵, Leu⁸)-bradykinin was previously reported as having multiphasic effects on arterial blood pressure in conscious trout and here we have demonstrated that it can antagonize the relaxation in rat arterial smooth muscle induced by canonical mammalian bradykinin. The discovery of (Arg⁰, Trp⁵, Leu⁸)-bradykinin in the defensive skin secretion of this amphibian completes the spectrum of vertebrate taxon-specific BRPs identified from this source.     

Inheritance of electrophoretic variants of tuber proteins in Solanum tuberosum haploids

Soluble tuber proteins were separated by discontinuous polyacrylamide gel electrophoresis on vertical slabs. Banding patterns of proteins stained with Coomassie Blue in 7.5% acrylamide gels (pH 4.3) were few and distinctive for haploids (2n = 2x = 24) derived from several cultivars (2n = 4x = 48). Katahdin and Chippewa haploids have only three different banding patterns for the eight fastest moving bands. The haploids have either the parental pattern (all eight bands) or one of two complementary banding patterns (four bands). The frequency of these patterns among the haploids indicates that the eight bands are controlled by one locus which is duplex (A¹A¹A²A²) in the parents. Haploids with the genotype A¹A² have eight bands. A¹A¹ haploids have four bands, and A²A² have the other four bands. Tawa haploids have in equal numbers either the eight (A¹A²) or four (A²A²) band pattern. Thus the genotype of Tawa is A¹A²A²A². The control of four bands by one allele could be explained by assuming that these alleles are involved in posttranslational modification or assembly of one or two protein species. Another explanation is that pseudoalleles or redundant genes produce the groups of protein bands. The eight proteins studied apparently are of similar molecular weight but differ in charge.     

Carbon-13 nuclear magnetic resonance spectra of carbohydrate oxirane derivatives

The ¹³C-chemical shifts and ¹J_C,H values of two series of carbohydrate oxirane derivatives, namely methyl 2,3-anhydro-ribo- and -lyxofuranosides and methyl 2,3-anhydro-4,6-O-benzylidene-manno- and -allopyranosides have been determined. The assignment of ¹³C resonances has been established mainly by the examination of the proton-coupled and the selective proton-decoupled spectra. The effect of the oxirane rings on the chemical shifts of β and γ carbon atoms (from the oxirane ring oxygen atom) has been observed. Large ¹J_C,H values associated with cis CH bonds adjacent to the oxirane rings relative to those of trans counterparts have been found.