Insect Floral Visitors of Ptelea trifoliata (Rutaceae) in Iowa, United States.

Ptelea trifoliata L., is a North American tree that supports insect communities through floral rewards. Our objectives were to determine the importance of insects as pollinators of P. trifoliata; describe the community of floral visiting insects of P. trifoliata in Iowa, where no such information was available; and to note insect preferences for male or female flowers. Over two years, inflorescences on 13 trees were covered with mesh bags before blooming and the amount of fruit produced was compared to uncovered inflorescences from the same trees. In one year, insects were collected from male and female trees with an insect vacuum every 3 h between 7 am and 7 pm from four sites in Iowa, USA between 30 May and 16 June 2020. In 2019 and 2020, almost no fruit set occurred from inflorescences covered with mesh bags while an average of 51.2 fruits formed on unbagged inflorescences (P < 0.0001), suggesting insects larger than the 600 µm pore diameters mesh were responsible for pollination of P. trifoliata. Insects from five orders, 49 families, and at least 109 species were collected. Most insects were Hymentoptera (48.3%) or Diptera (28.2%). Male flowers attracted 62.3% of all insects collected. Since most of the insects found visiting P. trifoliata were not bees, the floral rewards of the flowers may be a valuable resource for a wide variety of insects in the central United States.

First Report of Sclerotium rolfsii on Brassidium Hybrid Orchid.

Brassidium hybrid orchid leaves were sent to the University of Florida Plant Disease Clinic in the summer of 2002. Symptoms on leaves were a spreading, cottony, white mass of mycelium with necrotic centers 3 to 5 × 5 to 9 mm. Approximately 1% of leaves submitted were affected. Sclerotium rolfsii Sacc. was isolated from the affected leaves using acid potato dextrose agar (APDA) (1). Two plastic boxes were lined with wet paper towels and 6 uninoculated leaves were placed in each. Three leaves in each box were treated as controls and received 3 mm2 of APDA, while the other three leaves in each box received 3 mm2 of S. rolfsii culture on APDA. All leaves were misted with water and enclosed to maintain humidity. Twenty-four hours later, infection was visible on two treated leaves. Within 72 h, significant infection was visible on three of the six inoculated leaves. All control leaves remained uninfected. S. rolfsii was consistently reisolated from the inoculated leaves, fulfilling Koch's postulates. Over the past 12 months, S. rolfsii has been detected in 30% of commercial orchid nurseries as well as homeowner orchid collections in Miami-Dade County, Florida. No resistance to this disease in orchids has been reported. To our knowledge, this is the first report of S. rolfsii on this orchid hybrid. Reference: (1) J. Tuite. Media and nutrient solutions used by plant pathologist and mycologist. Page 53 in: Plant Pathological Methods Fungi and Bacteria. Burgess Publishing Company, Minneapolis, MN, 1969.

First Report of Dieback Caused by Verticillium dahliae on Blighia sapida in the United States.

Mature akee trees, Blighia sapida K. Koenig, in a local south Florida commercial orchard had wilt and dieback symptoms during spring 1999. A fungus isolated from the gray xylem root tissue on V8 agar was identified as Verticillium dahliae Klebahn at the Division of Plant Industry of the Florida Department of Agriculture and Consumer Services. Twenty akee seedlings were transplanted into 3.85-liter plastic pots and grown in a greenhouse at a daytime temperature of 28°C and nighttime temperature of 23°C. When plants were approximately 25 cm high, a 15-cm knife was used to sever roots in the four quadrants of each pot. Inoculum was made from a 2-week-old culture of V. dahliae on V8 agar and blended with 160 ml of sterile water, and 15 ml of this slurry was poured into the disturbed soil of each of 10 treated plants. A plate of uninoculated V8 agar was applied, as above, to 10 control plants. Plants were kept in the greenhouse. After 6 weeks, inoculated plants showed symptoms of leaf wilt, dieback and plant death. No symptoms were seen on control plants. V. dahliae was isolated directly from the gray vascular tissue of inoculated plants. The inoculation experiment was repeated three times, fulfilling Koch's postulates. To our knowledge, this is the first report of Verticillium dieback on B. sapida in the United States.

Accumulation of ENOD2-like transcripts in non-nodulating woody papilionoid legumes.

Japanese pagodatree (Styphnolobium japonicum [L.] Schott) and American yellowwood (Cladrastis kentukea Dum.-Cours.) Rudd are the first woody, non-nodulating papilionoid legumes shown to possess putative early nodulin 2 (ENOD2) genes. ENOD2 cDNAs from Japanese pagodatree (807 bp) and American yellowwood (735 bp) have 75% to 79% sequence identity to ENOD2 sequences and encode deduced proteins that possess conserved ENOD2 pentapeptides (PPHEK and PPEYQ). Lower percentages of glucose and higher percentages of histidine and valine suggest that SjENOD2 and CkENOD2 are different from other ENOD2s. Hybridization analyses indicate the clones represent ENOD2 gene families of two to four genes in Japanese pagodatree and American yellowwood genomes, and ENOD2-like transcripts were detected in stems and flowers, as well as roots. Only roots of control species that nodulate, Maackia amurensis Rupr. & Maxim. and alfalfa (Medicago sativa), produced pseudonodules after treatment with zeatin or 2,3,5-triiodobenzoic acid, an auxin transport inhibitor. Accumulation of MaENOD2 transcripts was enhanced during the first 10 d of treatment, but 2,3,5-triiodobenzoic acid and zeatin enhanced transcript accumulation after 30 d in roots of Japanese pagodatree and American yellowwood. Characteristics that distinguish ENOD2 gene families in basal, non-nodulating woody legumes from other ENOD2 genes may provide new information about the function of these genes during symbiotic and non-symbiotic organ development.

First Report of Aristastoma Leaf Spot on Desert Rose.

In the spring of 1995, a species of Aristastoma was isolated from foliar lesions of Adenium obesum that originated in a commercial nursery in Dade County, FL, where 100% of the crop was affected. Plant foliage had irregular, oval to circular, rusty brown, necrotic lesions 5 to 15 mm in diameter. Large leaf spots developed tan centers. An undescribed species of Aristastoma was isolated consistently from symptomatic plant material. The identity of the fungus was confirmed by the International Mycological Institute, Egham, England. Both in vivo and in vitro, the fungus has immersed mycelium, pale brown to hyaline, branched and septate. Pycnidia are 160 to 300 µm in diameter with prominent setae 75 to 125 µm surrounding the ostiole, with hyaline, 1 septate, conidia that are 25 to 30 × 3 to 4 µm. Pathogenicity was tested on shadehouse-grown, 8-month-old desert rose plants by spraying plants with a conidial suspension containing 104 conidia per ml. Inoculated plants developed foliar symptoms within 5 to 10 days that were consistent with those originally observed on the diseased plant samples. The pathogen was isolated from symptomatic tissue of inoculated plants. Species of Aristastoma are reported to cause foliar symptoms mostly on leguminous crops, and in Florida Aristastoma oeconomicum causes lesions on Vigna. This is the first report of this or any species of Aristastoma on Adenium obesum or any other member of the Apocynaceae.

Influence of hydroponic culture method on morphology and hydraulic conductivity of roots of honey locust.

The morphology and hydraulic conductivity of root systems of Gleditsia triacanthos L. var. inermis Willd. (honey locust) grown hydroponically in sand and solution cultures were compared. Total root system length was similar in the two cultures. However, root systems grown in solution had longer primary roots, fewer lateral roots and root hairs, and a greater distance between the tip of the primary root and the junction of the youngest secondary root and the primary root than root systems grown in sand. Hydraulic conductivities of root systems grown hydroponically for 21 or 35 days in sand or solution culture were similar. These findings show that different methods of hydroponic culture can affect root morphology without altering root resistance to water transport.

Diversity among Rhizobia Effective with Robinia pseudoacacia L.

The diversity of rhizobia that form symbioses with roots of black locust (Robinia pseudoacacia L.), an economically important leguminous tree species, was examined by inoculating seedling root zones with samples of soil collected from the United States, Canada, and China. Bacteria were isolated from nodules, subcultured, and verified to be rhizobia. The 186 isolates varied significantly in their resistance to antibiotics and NaCl, their growth on different carbohydrates, and their effect on the pH of culture media. Most isolates showed intermediate antibiotic resistance, the capacity to use numerous carbohydrates, and a neutral to acid pH response. Isolates had greater similarity within sampling locations than among sampling locations. The isolates were grouped by using numerical taxonomy techniques, and representative strains of 37 groups were selected. The mean generation times of these isolates ranged from 3 to 9 h, and the protein profile of each of the 37 isolates was unique. Nitrogen fixation, total nitrogen accumulation, and plant growth varied significantly among black locust seedlings inoculated with the representative isolates. We conclude that great variation exists among Rhizobium spp. that nodulate black locust, and selection of strains for efficiency of the symbiotic association appears possible.

Immunochemical studies of infectious mononucleosis. VII. Isolation and partial characterization of a glycopeptide from bovine erythrocytes.

The major sialoglycopeptide released from bovine erythrocytes by papain has been purified and characterized. The glycopeptide contains 82% by weight carbohydrate in molar ratios of galactose - 5.5:N-acetylglucosamine - 3.6:sialic acid - 2.6:N-acetylgalactosamine - 1.0. The carbohydrate and amino acid composition is quite different from the glycoprotein extracted from bovine erythrocyte stroma with hot 75% ethanol. The glycopeptide is devoid of reactivity with Paul-Bunnell heterophile antibody of infectious mononucleosis - an activity expressed to high degree on the bovine erythrocyte and associated with glycoprotein. The glycopeptide does react, however, with another antibody found in infectious mononucleosis as well as most normal human sera tested.

Isolation of plasma membrane glycoprotein from bovine thymocytes.

Glycoprotein was isolated from a purified thymocyte membrane preparation by two methods: lithium diiodosalicylate-phenol extraction and hot 75% ethanol extraction. A higher yield of membrane sialic acid was obtained by the latter method. The preparations had similar apparent molecular weights on sodium dodecyl sulfate gel electrophoresis. Both had similar receptor activities against a panel of hemagglutinins, although the 75% ethanol extract was more active on a weight basis. However, there were significant differences in carbohydrate and amino acid compositions of the two thymocyte extracts. The lithium diiodosalicylate-extracted material had much more glucose, ribose, and glycine than the ethanol extract. The glycoprotein preparations from thymocytes were quite distinct from the glycoprotein of bovine erythrocytes in both composition and receptor properties.

Immunochemical studies of infectious mononucleosis. VI. a radioimmunoassay for the detection of infectious mononucleosis heterophile antibody and antigen.

The coated-tube method of solid-phase radioimmunoassay has been adapted to the detection of heterophile antibodies and antigens of infectious mononucleosis. Disposable plastic hemagglutination trays were coated with purified glycoprotein from horse erythrocytes and the subsequent uptake of antibody from test sera was detected by radio-iodinated horse erythrocyte glycoprotein. In a preliminary survey of sera from patients with infectious mononucleosis and sera from controls, the assay proved highly sensitive and specific. The test system was also useful in a competitive binding assay for immunochemical studies of glycoproteins from other heterophile antigen-positive species.

Immunochemical studies of infectious mononucleosis. V. Isolation and characterization of a glycoprotein from goat erythrocyte membranes.

A glycoprotein was isolated from goat erythrocyte membranes by extraction with hot 75% ethanol. The glycoprotein was purified by ethanol precipitation, phosphocellulose chromatography gel filtration, ethyl:ether and chloroform:methanol extraction. In aqueous phosphate-buffered saline, pH 7, the glycoprotein was in an aggregated state with a sedimentation coefficient (S(obs)) to 1.5. Electrophoresis of the glycoprotein on polyacrylamide gels containing phosphate-buffered 0.1% SDS gave a single band, staining with both periodic acid Schiff (PAS) and Coomassie Blue (CB). The apparent m.w., calculated from retardation coefficient, was 25,000. Electrophoresis of the glycoprotein on 1% SDS gels buffered with Tris-acetate (pH 7.4) showed a major band of similar (23,500) apparent m.w. plus four other PAS- and CB-staining bands of lower mobility. With 131I-labeled glycoprotein, recovery of bands from gels, sialic acid analysis, heterophile antigen activity, and re-electrophoresis, it was shown that these additional bands were aggregated forms of a single or closely related glycoprotein species. The purified glycoprotein contained 50% carbohydrate with molar ratios of sialic acid:galactose:mannose:galactosamine:glucosamine of 3.1:2.1:0.1:1.6:1. The glycoprotein was highly reactive with the Paul-Bunnell heterophile antibody in the sera of patients with infectious mononucleosis, with Limulus polyphemus lectin and weakly ractive with wheat germ agglutinin. These reactivities were destroyed by neuraminidase treatment or by alkaline sodium borohydride. The native glycoprotein did not react with lectins from Canavalia enisformis, Phaseolus vulgaris, Ricinus communis, or Vicia graminea although it was reactive with the latter two after neuraminidase treatment.