Electrophoretic analysis of genetic variability in the house fly (Musca domestica L.)

Methods are described for the resolution of house fly, Musca domestica L., enzymes by vertical polyacrylamide gel electrophoresis. An electrophoretic survey in Ames, Iowa, of 51 loci distributed among 26 enzyme systems revealed that 40% of the loci are polymorphic. Observed and expected heterozygosities measured at 33 loci were 0.0981 and 0.1148, respectively. A significant deficiency of heterozygotes was noted at certain loci.Journal Paper No. J-11423 of the Iowa Agriculture and Home Economics Experiment Station, Ames. Project No. 2411.     

Nitrogen fertilization effects on dinitrogen fixation as influenced by legume species and proportion in legume-grass mixtures in Uruguay

Grasses grown in mixture with nodulated legumes often are N-limited, but N fertilization may result in reductions of N₂ fixation and legume stands. We studied N-fertilizer effects on N₂ fixation for three binary legume-grass mixtures in Uruguay. Replicated swards of white clover (Trifolium repens L.) (WC), red clover (Trifolium pratense L.) (RC), or birdsfoot trefoil (Lotus corniculatus L.) (BT), each in combination with tall fescue (Festuca arundinacea Schreb) (TF) at two legume proportions were sown in 1983 (Exp. 1) and 1984 (Exp. 2). In the fall of 1984, N treatments at 100 kg ha⁻¹ and controls were randomly assigned to subplots in Exp. 1 (established swards) and in Exp. 2 (at seeding). The soil for both experiments was a fine, montmorillonitic, mesic, Typic Argiudolls. Herbage fixed-N was estimated by ¹⁵N isotope-dilution with pure stands of TF as reference. In both experiments, N fertilization reduced the proportion of legume N derived from air (% Ndfa) and increased herbage yield only during the first 18 to 20 weeks after application. Fertilizer-N reduced annual fixed-N yield from 178 to 148 kg ha⁻¹ in Exp. 1 and from 65 to 29 kg ha⁻¹ in Exp. 2 Fixed-N yield for BT was markedly reduced by N in both experiments (33 to 53%), whereas for the clovers reduction was lesser in Exp. 1 (9 to 13%) than in Exp. 2 (46 to 64%). Negative effects of N on % Ndfa were more evident for the high legume proportion. We conclude that fertilization with 100 kg N ha⁻¹ reduced % Ndfa only for the immediate 18 to 20 weeks after application. Fertilizer-induced reduction of fixed-N yields lasted longer because of a more prolonged depression of legume proportion, especially for BT and for newly seeded swards. Journal Paper no. J.-13327 of the Iowa Agric. and Home Econ. Exp. Stn., Ames, U.S.A. (Project 2281). Supported in part by the Facultad de Agronomía, Montevideo, Uruguay; and the International Atomic Energy Agency, Vienna, Austria (Project URU/5/012). Journal Paper no. J.-13327 of the Iowa Agric. and Home Econ. Exp. Stn., Ames, U.S.A. (Project 2281). Supported in part by the Facultad de Agronomía, Montevideo, Uruguay; and the International Atomic Energy Agency, Vienna, Austria (Project URU/5/012).     

A method for determining the in vivo stability of Drosophila alcohol dehydrogenase (E.C.1.1.1.1.)

A rapid and accurate method of measuring the relative in vivo stability of Drosophila alcohol dehydrogenase is presented. The potential of this technique for examining posttranslational control of in vivo enzyme concentrations is discussed.This work was supported by NSF grant #DEB 7815466 to J.M.Journal Paper No. J-9977 of the Iowa Agriculture and Home Economics Experiment Station, Ames, Iowa. Project No. 2272.     

Phosphorus-32 bioelimination by arthropod predators fed labeled eggs ofHeliothis virescens [Lep.: Noctuidae]

Adults ofGeocoris punctipes (Say),Tropiconabis capsiformis Germar,Nabis roseipennis Reuter andColeomegilla maculata (DeGeer) were confined inside petri dishes and fed phosphorus-32 (^32p)-labeledHeliothis virescens (F.) eggs. Observations of bioelimination of^32p over a 72 h period allowed derivation of equations for predicting the number ofH. virescens eggs ingested by each species. Twenty-four to 72 h after eggs were eaten, the percentages of^32p eliminated ranged from ca. 14% forG. punctipes to 42 % forT. capsiformis. Cautious use of the results will aid researchers in assessing predation on^32p labeledHeliothis. Publication N^o 5935. Mississippi Agricultural and Forestry Experiment Station, Mississippi State, MS 39762.     

Seasonal distribution of topsoil ammonium and nitrate under legume-grass and grass swards

Losses of soil N through leaching and N₂ fixation by legumes often are related to soil nitrate concentration. The seasonal distribution of soil ammonium and nitrate concentrations under ungrazed legume-grass and grass swards were evaluated on two experiments that were established in 1983 (Exp. 1) and in 1984 (Exp. 2). Treatments were white clover (Trifolium repens L.) (WC), red clover (Trifolium pratense L.) (RC), and birdsfoot trefoil (Lotus corniculatus L.) (BT), each grown with tall fescue (Festuca arundicacea Schreb.) (TF) at two legume proportions, and a pure stand of TF. The concentrations of both forms of N were measured in the top 20-cm layer during 2 years in Exp. 1 and for 1 year in Exp. 2. The concentrations of nitrate and ammonium were least in winter and spring, and greatest in summer. The concentration of nitrate for the mixtures decreased in the order WC-TF, RC-TF, and BT-TF in both summers of Exp. 1 but there were no mixture differences in Exp. 2. The concentration of soil ammonium was not affected by the treatments applied. We conclude that the concentration of soil nitrate usually was small for these swards but became greater and often dependent on species and legume proportion during summer. The concentration of soil ammonium also was greater in summer but was not affected by species or legume proportion. Journal of Paper no. J.-13359 of the Iowa Agric. and Home Econ. Exp Stn., Ames. Project 2281. Supported in part by the Facultad de Agronomía, Montevideo, Uruguay. Journal of Paper no. J.-13359 of the Iowa Agric. and Home Econ. Exp Stn., Ames. Project 2281. Supported in part by the Facultad de Agronomía, Montevideo, Uruguay.     

Molecular-marker-facilitated investigation of host-plant response to Exserohilum turcicum in maize (Zea mays L.): components of resistance

RFLPs were used to investigate components of host-plant response to Exserohilum turcicum in 150 unselected F₂₃ lines of a B52/Mo17 maize population. Following inoculation with spore suspensions of the pathogen (race 0), components of disease development were measured and then quantitative trait mapping was performed to identify the location and effects of quantitative trait loci (QTLs) determining host-plant response. Components of interest were the average number of lesions per leaf, the average percent leaf tissue diseased (severity) and the average size of lesions (cm²). Based on a LOD threshold of 2.31 (P<0.05), the number of lesions appears to be associated with QTLs on chromosomes 1S, 3L, 5S. Severity was associated with analogous regions and, in addition, QTLs on chromosomes 7L and 8L. Most QTLs, for either of these two components, involve additive gene action and partial dominance or overdominance. In contrast, lesion size was associated with QTLs on chromosomes 7L and 5L; recessive gene action may be involved at 7L.Journal Paper No. J-15178 of the Iowa Agriculture and Home Economic Experiment Station, Ames, Iowa. Project No. 3134     

Developmental genetics of a P element induced allele of suppressor-of-forked in Drosophila melanogaster

Summary In this paper we describe a new allele of suppressor of forked, su(f) ^hd37, referred to as hd37, which was isolated in a hybrid dysgenesis mutation screen and is shown to be P induced by its high frequency of reversion in hybrid dysgenic crosses, and by in situ hybridization. hd37 suppresses forked and fails to complement the forked suppression of known su(f) alleles. However, it complements the recessive lethality of alleles in both of the su(f) lethal complementation groups. We also describe a new phenotypic effect of su(f) alleles, the enhancement of Minute(3)i ⁵⁵. Recessive lethal alleles enhance the lethal effects of this Minute, but hd37 does not. The temperature sensitive period for forked bristle suppression by hd37 was found to be very narrow, consisting of a short interval (12–18 h) immediately before bristle formation. These results suggest that the several genetic functions associated with this locus may be genetically separable.Journal paper No. J-12137 of the Iowa Agriculture and Home Economics Experiment Station, Ames, Iowa. Project No. 2746     

Novel lignocellulolytic ability of Candida utilis during solid-substrate cultivation on apple pomace

Lignocellulolytic enzymes from conventional and non-conventional yeasts are not commonly studied, and they have never been described for Candida utilis species. After solid-substrate cultivation of C. utilis (CCT 3469) on apple pomace, degradation of cellulose, pectin and lignin fragments was observed. Production of the main lignocellulolytic enzymes by C. utilis was investigated and high activity for pectinase (239 U ml^–1) as well as a significant manganese-dependent peroxidase (19.1 U ml^–1) activity was found. Low cellulase (3.0 U ml^–1) and xylanase (1.2 U ml^–1) activities were also observed suggesting that C. utilis may have lignocellulose degradation ability.     

Effectiveness of Ethylenediamine-N(o-hydroxyphenylacetic)-N′(p-hydroxyphenylacetic) acid (o,p-EDDHA) to Supply Iron to Plants

The Fe chelate o,p-EDDHA/Fe³⁺, in addition to o,o-EDDHA/Fe³⁺, was found recently to be a component of commercial EDDHA/Fe³⁺ chelates. The European Regulation on fertilisers has included o,p-EDDHA as an authorized chelating agent. The efficacy of o,o-EDDHA/Fe³⁺, o,p-EDDHA/Fe³⁺ and EDTA/Fe³⁺ chelates as Fe sources in plant nutrition was studied. Iron-chelate reductase (FC-R) in young cucumber plants (Cucumis sativus L.) roots reduced o,p-EDDHA/Fe³⁺ faster than o,o-EDDHA/Fe³⁺, EDTA/Fe³⁺ and a commercial source of EDDHA/Fe³⁺. The o,p-EDDHA/Fe³⁺ chelate was also more effective than the o,o-EDDHA/Fe³⁺ in decreasing the severity of Fe-deficiency chlorosis in leaves of young soybean (Glycine max L.) plants grown hydroponically. The o,p-EDDHA ligand was more effective in the short-term than the EDTA and o,o-EDDHA ligands at dissolving Fe from selected Fe minerals and soils. However, the ultimate quantity of dissolve Fe was greatest with the o,o-EDDHA ligand.     

Temporal and spatial trends in allozyme frequencies in house fly populations,Musca domestica L.

Summary Allelic and genotypic frequencies were sampled from a single age class of the common house fly, Musca domestica L., at five farms on six dates from July 6 to October 12, 1982. Allozymes at six loci were resolved with vertical polyacrylamide gel electrophoresis. No consistent departures from random mating were detected. No consistent linkage disequilibrium was observed. Allele frequencies at the farms changed in independent and unpredictable ways. Gene frequencies at the five farms were initially divergent, converged in midsummer, and then progressively diverged. The divergence occured in mid-August when fly populations were large. Variation in gene frequencies at adjacent farms accounted for a large proportion of the variance in allele frequencies among all farms. These observations are consistent with the hypothesis that allele frequencies in young adult flies reflected the habitat in which they matured as larvae.Journal Paper No. 11718 of the Iowa Agriculture and Home Economics Experiment Station, Ames, Iowa, Project No. 2411     

Effect of environmental alcohol on in Vivo properties of Drosophila alcohol dehydrogenase

The effects of environmental 2-propanol on the in vivo properties of Drosophila alcohol dehydrogenase (E.C. 1.1.1.1.) are presented. Exposed flies were found to exhibit a significant decrease in ADH specific activity with a concomitant increase in the enzyme's relative in vivo stability and concentration. The possible adaptive significance of the observed responses is discussed.This work was supported by NSF grant #DEB 7815466 to J.M. Journal Paper No. J-9979 of the Iowa Agriculture and Home Economics Experiment Station, Ames, Iowa. Project No. 2272.     

Chromosome labeling with transposable elements in maize

Transposable elements randomly insert into a targeted locus at a frequency of 10^-6 to 10^-5. The En element has been shown in previous studies to transpose more frequently into closely linked sites. Thus, it is appropriate to place an En element onto each of the 20 chromosome arms in maize to maximize tagging efficiency. This is called chromosome labeling for tagging purposes with transposons. After a chromosome arm has been labeled with a transposon, genes residing in that arm will have a greater chance to be tagged by the transposon. To date, all of the maize chromosome arms have been labeled with at least one of five Encontaining alleles. The elements were linked to the arms using reciprocal translocations. The usage of these arm-labeled lines is discussed in the context of gene tagging.Journal Paper No. 15224 of the Iowa Agriculture and Home Economics Experiment Station, Ames, Iowa; Project No. 3176     

Vegetative growth and sporulation ofBipolaris sorokiniana on sequentially older infected leaves ofPoa pratensis exposed to postemergence herbicides

Poa pratensis was exposed to the postemergence herbicides 2,4-D, MCPP, and dicamba at concentrations of 10^–6 M applied to the soil surface. Sequentially older leaf blades were inoculated withBipolaris sorokiniana and detached to determine the effect of the herbicides on saprophytic hyphal growth and sporulation on the tissue of each older leaf. 2,4-D and dicamba stimulated hyphal growth in vitro from leaf tissue of all ages; MCPP had no effect on hyphal growth. All herbicides increased sporulation byB. sorokiniana on leaf tissue of all ages. Both hyphal growth and sporulation increased progressively on tissue from sequentially older leaves ofP. pratensis exposed to dicamba.Journal Paper No. J-14985 of the Iowa Agriculture and Home Economics Experiment Station, Ames, Iowa, USA, Project No. 2616.     

Release in Manitoba,Canada oftownesilitus bicolor [HYM.: Braconidae], an European parasite ofPhyllotreta spp. [Col.: Chrysomelidae]

Townesilitus bicolor (Wesmael), a parasite of some crucifer-infesting species ofPhyllotreta in Europe, was released in Manitoba Canada in 1978–83, in an attempt to reduce populations ofPhyllotreta cruciferae (Goeze) andP. striolata (Fab.). Releases totalled 1936 adults ofT. bicolor and approximately 2639Phyllotreta collected in Manitoba and parasitized in the laboratory. No evidence of establishment was found up to 1985 at either of the 2 release sites. The small numbers of parasite released, and dispersal of the host population twice each year, have reduced the probability of the parasite becoming established and of establishment being detected. Contribution n^o 1248     

Molecular cloning and characterization of the alcohol dehydrogenase ADH1 gene of Candida utilis ATCC 9950

The alcohol dehydrogenase gene (ADH1) of Candida utilis ATCC9950 was cloned and expressed in recombinant Escherichia coli. C. utilis ADH1 was obtained by PCR amplification of C. utilis genomic DNA using two degenerate primers. Amino acid sequence analysis of C. utilis ADH1 indicated that it contained a zinc-binding consensus region and a NAD(P)⁺-binding site, and lacked a mitochondrial targeting peptide. It has a 98 and 73% identity with ADH1s of C. albicans and Saccharomyces cerevisiae, respectively. Amino acid sequence analysis and enzyme characterization with various aliphatic and branched alcohols suggested that C. utilis ADH1 might be a primary alcohol dehydrogenase existing in the cytoplasm and requiring zinc ion and NAD(P)⁺ for reaction.     

Purification and infectivity ofEntomophaga grylli (Fresenius) Batko Pathotype 2 againstMelanoplus differentialis (Thomas) [Ort.: Locustidae]

The life stages ofEntomophaga grylli (Fresenius) Batko Pathotype 2 were purified and separated by centrifugation in Percoll^R density-gradient medium. The ranges of buoyant densities for germinated resting spores, germ conidia, and resting spores respectively were: 1.040–1.050, 1.055–1.085, and 1.080–1.120 g/ml. Cuticular invasion by germinated germ conidia was the means by whichMelanoplus grasshoppers became infected. Scanning electron micrographs revealed germination of germ conidia on the visible host integument at 100% RH, but not at 90% RH. Significantly higher mortality (P<0.05) was obtained after 3 weeks with grasshoppers incubated in constant light than in constant dark for 24 h following treatment. The disease was not transmitted by ingestion of any life stage. Contribution N^o 85-153-J, Department of Entomology. Agricultural Experiment Station, Kansas State University, Manhattan, KS 66506.     

Conditional lethality involving a cytoplasmic mutant and chlorophyll-deficient malate dehydrogenase mutants in soybean

Summary Conditional lethality in soybean, Glycine max (L.) Merr., occurred in F₂ plants when cytoplasmicchlorophyll mutant Genetic Type T275 was the female parent and when either nuclear mutants T253 or T323 plants were the male parents. Mutant T253 [Mdh1-n (Urbana) y20 (Urbana) k2] is missing two of three mitochondrial malate dehydrogenase isozymes [Mdh1-n (Urbana)] and has yellowish-green leaves [y20 (Urbana)] and a tan-saddle pattern seed coat (k2). Mutant T323 [Mdh1-n (Ames 2) y20 (Ames 2)] also is missing two of three mitochondrial malate dehydrogenase isozymes [Mdh1-n (Ames 2)] and has yellowishgreen leaves [y20 (Ames 2)], but has yellow seed coat (K2). Mutants T275, T253, and T323 are viable both in the field and glasshouse. The genotypes cyt-Y2 Mdh1-n (Urbana) y20 (Urbana) k2/Mdh1-n (Urbana) y20 (Urbana) k2 and cyt-Y2 Mdh1-n (Ames 2) y20 (Ames 2)/Mdh1-n (Ames 2) y20 (Ames 2) are conditional lethals. These genotypes are lethal under field conditions, but plants survive in reduced light under shadecloth in the glasshouse. We do not know if their interaction with cyt-Y2 is due to Mdh1-n, y20, or Mdh1-n y20. The reciprocal cross (cyt-Y2 as male parent) gives viable genotypes. These conditional lethal genotypes should be useful for studies on the interaction between organelle and nuclear genomes.This is journal paper no. J-14777 of the Iowa Agriculture and Home Economics Experiment Station, Ames, IA 50011-1010. Project 2985     

Peptide synthesis using o-nitrophenylsulfenyl N-carboxy alpha-amino acid anhydrides. Sequential oligopeptides having alternate gamma-methyl L-glutamyl and L-phenylalanyl residues.

A series of sequential oligopeptides having the sequence alternating γ-methyl L -glutamyl and L -phenylalanyl residues have been successfully prepared by a rapid method involving the reaction of o-nitrophenylsulfenyl N-carboxy α-amino acid anhydrides with amino acid and peptide esters. The sequential oligopeptides, which are interesting from a conformational aspect, were obtained in optical pure forms above 74% yields. This result demonstrates that the o-nitrophenylsulfenyl N-carboxy α-amino acid anhydride method is especially useful for easy synthesis of protected oligopeptides with o-nitrophenylsulfenyl group.     

Chemoenzymatic synthesis of stable isotope labeled UDP-N-[2H]-acetyl-glucosamine and [2H]-acetyl-chitooligosaccharides

Labeled UDP-GlcNAc and chitooligosaccharides should be powerful tools for studies of N-acetylglucosaminyltransferase such as chitin synthases. We describe here a rapid, inexpensive and a common strategie for the chemoenzymatic synthesis of uridine 5′-diphospho-N-[²H]-acetyl-glucosamine and the chemical preparation of N-[²H]-acetyl chitooligosaccharides (from 2 to 5 mers). Deuterated UDP-GlcNAc analogue was tested as chitin synthase substrate and it exhibited an incorporation level in chitin as the natural substrate. Deuterium labeling of carbohydrates present different advantages: it is a stable isotope and allows glycosyltransferase mechanism studies by a mass spectrometry approach.     

Studies of chloroplast development in four maize mutants defective in chlorophyll biosynthesis

Four mutants of maize (Zea mays L.) defective in chlorophyll biosynthesis have been analyzed with regard to the sites of their lesions and their effects on chloroplast development. Two yellow mutants, which accumulate no detectable porphyrin precursors when grown in darkness, are defective in the conversion of protoporphyrin IX to magnesium protoporphyrin. Etioplasts of these mutants may develop elaborate lamellar membrane systems, but prolamellar bodies are never observed. Two mutants, which are necrotic when grown under illumination, develop normal (non-necrotic) leaf tissue in the dark and accumulate a small amount of magnesium protoporphyrin monomethyl ester, corresponding approximately to the amount of protochlorophyllide accumulated by normal plants. The etioplasts of these mutants contain noncrystalline bodies. The implications of these observations with respect to chloroplast development are discussed.Journal Paper No. J-9136 of the Iowa Agriculture and Home Economics Experiment Station, Ames, Iowa Project No. 2035