Symptomatology and histopathology of fibrous roots of rough lemon (citrus limon) infected with Fusarium solani

Fibrous-root decay and epidermal and cortical sloughing were common on blight trees in two citrus groves with severe symptoms in October 1975. These symptoms were present to varying extent on blight trees in other groves, and some fibrous-root decline also was present on apparently healthy trees. Fusarium solani was present in declining fibrous roots of diseased and healthy trees and occurrence appeared to be limited to the fibrous roots. Fusarium infection resulted in early cortical degeneration, leaving epidermal sleeves on intact, infected steles. Generally, in the xylem and cortex with advanced symptoms, only chlamydospores were present. Sites of early infection conained abundant hyphae and immature chlamydospores. Hyphae penetrated the cortex intracellularly and intercellularly, and all cell types of the xylem appeared to be infected predominantly through pits. Fusarium was found on the surface of the epidermis and in broken epidermal cells of healthy-appearing and diseased roots.This paper reports the results of research only. Mention of a pesticide in this paper does not constitute a recommendation for use by the U.S. Department of Agriculture, nor does it imply registration under FIFRA as amended. Mention of a trademark or proprietary product does not constitute a guarantee or warranty of the product by the U.S. Department of Agriculture and does not imply its approval to the exclusion of other products that may also be suitable.     

Isolation, characterization and optimization of culture parameters for production of an alkaline protease isolated from Aspergillus tamarii

Aspergillus tamarii expresses an extracellular alkaline protease that we show to be effective in removing hair from cattle hide. Large quantities of the enzyme will be required for the optimization of the enzymatic dehairing process so the growth conditions for maximum protease expression by A. tamarii were optimized for both solid-state culture on wheat bran and for broth culture. Optimal protease expression occurred, for both cultural media, at initial pH 9; the culture was incubated at 30 °C for 96 h using a 5% inoculum. The crude enzyme was isolated, purified and characterized using MALDI TOF TOF. The alkaline protease was homologous to the alkaline protease expressed by Aspergillus viridinutans. Mention of trade names or commercial products in this publication is solely for the purpose of providing specific information and does not imply recommendation or endorsement by the U.S. Department of Agriculture.     

Co-production of Schizophyllan and Arabinoxylan from Corn Fiber

Schizophyllum commune strain ATCC 38548 grew well on a medium containing alkaline H₂O₂-pretreated corn fiber as a sole carbon source, and clarified the culture medium within 7 days. The strain preferentially utilized the starch component of corn fiber for growth and production of schizophyllan. Culture supernatants contained approx. 50 mg schizophyllan and 200 mg arabinoxylan per g corn fiber. These polysaccharides were recovered separately by differential precipitation with ethanol. USDA - Mention of trade names or commercial products in this article is solely for the purpose of providing specific information and does not imply recommendation or endorsement by the U.S. Department of Agriculture. Revisions requested 29 November 2005; Revisions received 24 January 2006     

Simplified soy molasses-based medium for reduced-cost production of sophorolipids by <Emphasis Type="Italic">Candida bombicola</Emphasis>

A simplified medium containing only soy molasses and oleic acid as ingredients was developed for the production of sophorolipids (SLs) from Candida bombicola. We achieved a product yield of 53 ± 3 g of purified sophorolipids per liter of starting culture volume, which is 71 ± 4% of the yield obtained with growth medium that also additionally contains the costly yeast extract and urea as nitrogen source. The large majority of the SL components existed in the lactone form (87%), and the predominant component is SL containing (ω-1)-hydroxyoleic acid as the lipid moiety. The study demonstrated for the first time the usefulness of the low-value soy molasses as a combined nitrogen- and carbon-source for SL production at a reduced cost. Mention of trade names or commercial products in this article is solely for the purpose of providing specific information and does not imply recommendation or endorsement by the U.S. Department of Agriculture.     

Morphogenetic responses obtained from a variety of somatic explant tissues of data palm

Shoot tip, bud, leaf, stem and root explants from bearing trees, offshoots, seedlings, and asexual plantlets ofPhoenix dactylifera L. were cultured on modified Murashige and Skoog nutrient media containing 3 g/l activated charcoal, 100 mg/l 2,4-dichlorophenoxyacetic acid, 3 mg/l N ⁶-(Δ²-isopentyl)adenine to obtain callus. Differential morphogenetic responses were obtained from calli dependent on the explant type and parent source. Subcultured shoot tips and leafy lateral buds callus on nutrient media devoid of charcoal and supplemented with 0.1 mg/l α-naphthaleneacetic acid (NAA) produced adventitious plantlets. Subcultured leaf calli produced roots only. Root callus failed to exhibit any morphogenetic response upon subculturing. Undifferentiated non-leafy buds and stem tissues did not give rise to callus, regardless of the parent source. Generally, the best callus and embryogenetic responses from explants were obtained from seedling and plantlet parent sources. Similarly, organogenetic responses such as root formation and shoot development from shoot tips cultured on media containing 10 mg/l NAA were also related to the parent explant source. Mention of a trademark or proprietary product in the paper does not constitute a guarantee or warranty of the product by the U.S. Department of Agriculture and does not imply its approval to the exclusion of other products that may also be available.     

Stimulation of plant growth and gutta content in Eucommia ulmoides Oliv. by 2-diethylaminoethyl-3,4-dichlorophenylether [DCPTA]

The application of 2000 ppm 2-diethylaminoethyl-3,4-dichlorophenylether [DCPTA] to greenhouse-grown Eucommia ulmoides Oliv. plants resulted in an 18% increase in the gutta content. Leaf area and plant height were also enhanced. Field studies employing 100 ppm of a proprietary regulator, FVCL2, produced a 20% increase in leaf gutta.Reference to a company or product name does not imply approval or recommendation of the product by the U.S. Department of Agriculture to the exclusion of others that may be suitable.     

USE OF NATIVE PLANTS FOR REMEDIATION OF TRICHLOROETHYLENE: I. DECIDUOUS TREES

Phytoremediation of trichloroethylene (TCE) can be accomplished using fast-growing, deep-rooting trees. The most commonly used tree for phytoremediation of TCE has been the hybrid poplar. This study looks at native southeastern trees of the United States as alternatives to the use of hybrid poplar. The use of native trees for phytoremediation allows for simultaneous restoration of contaminated sites. A 2-mo, greenhouse-based study was conducted to determine if sycamore (Plantanus L.), eastern cottonwood (Populus deltoides), sweetgum (Liquidambar styraciflua L.), and willow (Salix sachalinensis) trees possess the ability to degrade TCE by assessing TCE metabolite formation in the plant tissue. In addition to the metabolic capabilities of each tree species, growth parameters were measured including change in height, water usage, total fresh weight of each tissue type, and calculated total leaf surface area. Willow trees had the greatest increase in height among all trees tested; however, at higher concentrations TCE inhibits growth. Sycamore trees had the highest overall leaf surface area and total biomass, which correlated with sycamore trees also having the highest average water usage over the course of the experiment. Carbon tubes used to sample transpiration gases from sycamore, sweetgum, and cottonwood trees did not contain detectable levels of TCE. Tenex sample collection tubes used to sample willow trees during TCE exposure showed average TCE concentrations of up to 0.354 ng TCE cm^?2 leaf tissue. All exposed trees contained TCE in the root, stem, and leaf tissues. The concentration of TCE remaining in tissues at the conclusion of the experiment varied, with the highest levels found in the roots and the lowest levels found in the leaves. Metabolites were also observed in different tissue types of all trees tested. The highest concentrations of trichloroacetic acid were observed in the leaves of the sycamore trees and cottonwood trees. Based on the growth parameters tested and the ability to metabolize TCE, sycamore and native cottonwood species are the best candidates for phytoremediation from this study.     

Biosynthesis of labeled fumonisins in liquid cultures of Fusarium moniliforme

Fumonisins were readily produced in cultures of Fusarium moniliforme using a defined liquid medium. Addition of 200 mg of d₃-methyl L-methionine to 100-ml cultures of F. moniliforme gave increased overall yields and high levels of deuterium (²H) incorporation into fumonisin B₁. Approximately 90% of the resulting fumonisin B₁ contained 6 deuterium atoms, while 9% of the product contained 3 deuterium atoms. Deuterium was shown to be incorporated exclusively in the methyl groups of the fumonisin backbone. The addition of as little as 5 mg of labeled methionine stimulated fumonisin production, but only about 5% of the fumonisin produced contained 3 deuterium atoms.Abbreviations ELEM equine leukoencephalomalacia Mention of companies or products by name does not imply their endorsement by the US Department of Agriculture over others not cited.     

Aflatoxin contamination caused by natural fungal infection of preharvest corn

Summary Aflatoxin contamination of developing corn (Zea mays L.) kernels caused by natural infection byAspergillus flavus Link ex Fries was studied in hybrids developed for the U.S. corn belt and for the southern U.S. and grown at diverse locations in 1977. Planting dates were staggered to examine the effect of crop maturity on infection by the toxin-producing fungus. A broad range of toxin values was observed at harvest; some levels exceeded the highest that had been previously recorded in corn. The highest concentration of aflatoxin B₁ detected was 8030 ppb. Levels of toxin differed significantly among planting dates in Florida and Georgia; the second planting date at these locations contained the highest toxin levels. Elevated concentrations of toxin were characteristic of kernel samples from southern locations and southeast Missouri; at these locations samples from hybrids developed for the south had significantly lower levels of toxin than hybrids developed for the corn belt. Ears with heavy insect damage had higher toxin levels than ears with less evidence of insect attack.Mention of firm names or trade products does not imply that they are endorsed or recommended by the U.S. Department of Agriculture over other firms or similar products not mentioned.     

Insertion of a heterologous gene construct into a non-functional ORF of the Streptococcus thermophilus chromosome

An integrative vector was constructed for inserting heterologous genes within a non-functional open reading frame (ORF) on the chromosome of Streptococcus thermophilus. The vector, pINTRS, contained a temperature sensitive origin of replication and an erythromycin resistance gene for initial selection in S. thermophilus. The region of the vector containing unique cloning sites, for insertion of recombinant genes, was flanked by homologous DNA sequences corresponding to a pseudogene in S. thermophilus to facilitate chromosomal integration. The gene encoding green fluorescent protein, regulated by a plasmid borne hsp promoter of S. thermophilus, was cloned into pINTRS to demonstrate proper functioning of the vector. Mention of trade names or commercial products in this publication is solely for the purpose of providing specific information and does not imply recommendation or endorsement by the U.S. Department of Agriculture.     

Purification and characterization of a family 5 endoglucanase from a moderately thermophilic strain of Bacillus licheniformis

Strains of thermophilic bacilli were screened for cellulolytic activity by gel diffusion assay on selective medium at 55°C. Strain B-41361, identified as a strain of Bacillus licheniformis, displayed activity against carboxymethylcellulose. Zymogram analysis demonstrated several catalytically active polypeptides with the most prominent species having a mass of 37 kDa. The enzyme was purified 60-fold with a 17% yield and specific activity of 183 U/mg. The amino terminal sequence was homologous to members of glycoside hydrolase family 5. Optimal temperature was 65°C (measured over 30 min), but the enzyme was most stable at 60°C, retaining greater than 90% activity after one hour. The enzyme had a broad pH range, with maximal activity at pH 6.0, 75% maximal activity at pH 4.5, and 40% at pH 10. The enzyme hydrolyzed p-nitrophenylcellobioside, barley β-glucan, and lichenan, but no activity was detected against avicel or acid-swollen cellulose.Mention of a trade name or commercial products in this publication is solely for the purpose of providing specific information and does not imply recommendation or endorsement by the U.S. Department of Agriculture.     

Inhibition of some mycotoxigenic fungi by iturin A,a peptidolipid produced by Bacillus subtilis

Bacillus subtilis produces peptidolipid compounds of the iturin group that have been shown to have antifungal properties, but not all fungal species are sensitive to these compounds. In this study, the activity of iturin A, produced by B. subtilis strain B-3, was tested. Paper disks impregnated with various concentrations of iturin A were placed on agar plates seeded with conidia of toxigenic species of Fusarium, Gerlacia, Penicillium or Aspergillus. Most isolates were inhibited at iturin A concentrations as low as 4 g/disk. Penicillium italicum, P. vindicatum, A. ochraceus and A. versicolor were most strongly inhibited by the iturin whereas P. citrinum and A. parasiticus were least sensitive to iturin A.Mention of a trademark or proprietary product does not constitute a guarantee or warranty by the US Department of Agriculture and does not imply approval to the exclusion of other products that may also be suitable.     

A new fumonisin from solid cultures of Fusarium moniliforme

A new fumonisin has been isolated from Fusarium moniliforme isolate MRC826 grown on corn. It was shown by NMR and mass spectrometry to be an isomer of fumonisin B₂ that has free hydroxyl groups at C-3 and C-10 instead of the normal C-3 and C-5. This new fumonisin was detected in cultures of most isolates of F. moniliforme that were examined and was usually present at concentrations similar to those of fumonisin B₂. Two isolates of F. moniliforme that produce significantly higher levels of this new isomer were identified.Abbreviations ELEM equine leukoencephalomalacia Mention of companies or products by name does not imply their endorsement by the US Department of Agriculture over others not cited.     

Ultrastructure of primary sporidia of a wheat-bunt fungus,Tilletia caries,during ontogeny and mating

Summary Primary sporidia ofTilletia caries (DC.) Tul. are borne on denticles at the tips of promycelia. The promycelia contain many small vacuoles and mitochondria and numerous lipid bodies. As the primary sporidia develop, the promycelial cytoplasm passes into the nascent cells. Septa develop between the bases of mature sporidia and the tips of the denticles. Sporidia that abscise from the denticles commonly have prominent birth scars at their bases. The sporidia have very thin walls, few vacuoles, attenuated mitochondria, and numerous lipid bodies. Conjugation pegs are generally produced by both members of a conjugating pair of sporidia and there are bud scars where they emerge from the sporidia. The sporidial walls are apparently hydrolyzed during emergence of the pegs. Vesicles are sometimes present at the tips of the conjugation pegs and, before fusion, electron-dense accumulations are sometimes observed between the tips of adjacent pegs. The approaching conjugation pegs are precisely aligned prior to fusion, suggesting polar communication. The walls of the conjugation pegs fuse and then are hydrolyzed. Fused sporidia are relatively homogeneous in content. The nucleus in a sporidum is often close to the conjugation tube and occasionally is partly within the fusion tube.Cooperative investigations of the Oregon Agricultural Experiment Station, Brigham Young University, and Science and Education Administration-Agricultural Research, U.S. Department of Agriculture. Technical Paper No. 4,934 of the Oregon Agricultural Experiment Station. Mention of a trademark or proprietary product does not constitute a guarantee or warranty of the product by the U.S. Department of Agriculture and does not imply its approval to the exclusion of other products that may be suitable.     

Effect of 20-hydroxyecdysone and diflubenzuron on chitin production by a cockroach cell line

Summary Twelve insect cell lines were tested for their ability to synthesize chitin. Three of the 7 lepidopteran lines tested (UMN-PIE, IAL-PID2, MRRL-CH) produced a hyamine-resistant material, that was digested by chitinase. The material did not withstand a more rigorous base digestion, and 20-hydroxyecdysone and diflubenzuron had no consistent effect on the production of the, material. One of the 5 cockroach cell lines (UMBGE-4), which is an ecdysone-producing vesicle line, produced a material resistant to a strong base which was degraded to chitobiose andN-acetylglucosamine by chitinase. Production of this material by the cells is increased by 20-hydroxyecdysone and inhibited by diflubenzuron. The UMBGE-4 vesicles are covered with microvilli which bear membrane plaques and produce extra cellular material that resembles insect cuticle. Published with the approval of the Director of the North Dakota Agricultural Experiment Station as journal article No. 1622. Mention of a company name or propiertary product does not imply endorsement, by the U.S. Department of Agriculture.     

Effect of salt nutrients on mannitol production by Lactobacillus intermedius NRRL B-3693

The effects of four salt nutrients (ammonium citrate, sodium phosphate, magnesium sulfate, and manganese sulfate) on the production of mannitol by Lactobacillus intermedius NRRL B-3693 in a simplified medium containing 300 g fructose, 5 g soy peptone, and 50 g corn steep liquor per liter in pH-controlled fermentation at 5.0 at 37°C were evaluated using a fractional factorial design. Only manganese sulfate was found to be essential for mannitol production. Added manganese sulfate concentration of 0.033 g/l was found to support maximum production. The bacterium produced 200.6±0.2 g mannitol, 61.9±0.1 g lactic acid, and 40.4±0.3 g acetic acid from 300 g fructose per liter in 67 h.Mention of trade names or commercial products in this article is solely for the purpose of providing specific information and does not imply recommendation or endorsement by the U.S. Department of Agriculture.     

Season long intraplant epizootics of entomopathogens,Beauveria bassiana andNosema pyrausta,in a corn agroecosystem

Intraplant epizootics of entomopathogens,Beauveria bassiana (Balsamo) Vuillemin, andNosema pyrausta (Paillot) were studied in a corn,Zea mays L., agroecosystem. Egg masses of the European corn borer,Ostrinia nubilalis (Hübner), infected withN. pyrausta were placed on midwhorl-stage corn plants. Conidia ofB. bassiana were applied in an aqueous suspension. Frass from the initial insects remaining within the plants was contaminated with sufficientN. pyrausta spores to infest 80% of the filial generation in each year of a 2-yr study. Viability ofN. pyrausta within the frass was monitored throughout the winter. Potential for impact of this inoculum on the filial generation is discussed. Conidia from cadavers of the European corn borer that were killed by the initial inoculum ofB. bassiana and/or conidia from the initial inoculum ofB. bassiana significantly reduced tunneling by the filial generation of the European corn borer. However, neither the concentration ofB. bassiana nor the age of the larvae exposed toB. bassiana, had any significant (P<.05) effect on tunneling by the 2nd-generation larvae. This paper reports the results of research only. Mention of a pesticide in this paper does not constitute a recommendation for use by the U.S. Department of Agriculture or cooperators, nor does it imply registration under FIFRA as amended.     

Susceptibility of the parasitoidMicroplitis croceipes [Hymenoptera: Braconidae] to field rates of selected cotton insecticides

Microplitis croceipes (Cresson), a parasitoid ofHeliothis spp., was treated topically with field rates of 5 formulated insecticides commonly used in cotton to controlHeliothis spp. Treatment with the pyrethroid fenvalerate, a mixture of the formamidine chlordimeform plus fenvalerate, and the carbamate thiodicarb resulted in nearly 100% survival at both the lowest and highest field rates recommended for these insecticides. The organophosphate acephate and the carbamate methomyl were extremely toxic to adultM. croceipes, causing 100% mortality at the lowest recommended field rates. Comparisons are made to previously reported laboratory toxicity data for some of these insecticides for adultM. croceipes. Choice of insecticides to control pyrethroid-resistantHeliothis spp., and the effects of these insecticides on adultM. croceipes survival, are discussed. This article reports the results of research only. Mention of a proprietary product does not constitute endorsement or a recommendation for its use by the U. S. Department of Agriculture.     

Mapping of beta-tubulin genomic sequences in hexaploid oat (Arena sativa L.)

Summary The allohexaploid nature of Avena sativa L. (2n=6x=42) and the availability of aneuploid lines was exploited in designing a strategy for mapping beta-tubulin sequences in the oat genome. Evidence for a minimum of eight beta-tubulin genes was obtained by Southern-blot analysis. Three betatubulin sequences were localized to chromosomes using DNA from monosomic and nullisomic lines in the variety Sun II. One sequence was localized to the chromosome missing in nullisome I. Two other sequences were mapped to satellite chromosome 2, the chromosome that is missing in nullisome VIII and to which one ribosomal RNA gene cluster had previously been mapped. Restriction fragments carrying these two beta-tubulin genomic sequences and the cluster of ribosomal RNA sequences were missing in DNA from nullisomics VIII, IX and X, suggesting that all three nullisome classes are deficient for an identical chromosomal segment that includes these three loci. This study demonstrates how molecular analyses can be used to characterize aneuploid stocks and to better define their genetic constitution.Mention of a trademark, proprietary product, or vendor does not constitute a guarantee or warranty of the product by the U.S. Department of Agriculture or the University of Minnesota and does not imply its approval to the exclusion of other products or vendors that may be suitable