A method for wet-ashing small plant samples

Summary An inexpensive but efficient and fast method is described for the wetashing of small samples of plant materials.Contribution No. 582, Department of Botany and Plant Pathology, Kansas Agricultural Experiment Station. Botany serial No. 744.     

An improved fume hood for perchloric acid digestions of biological materials

Summary An all-glass hood that can be used for perchloric acid digestion of small samples of biological materials is described. It offers an efficient, rapid inexpensive technique for wet ashing.Contribution No. 624, Department of Botany and Plant Pathology, Kansas Agricultural Experiment Station. Botany Serial No. 781.     

Uptake of sulphur-35 by vesicular-arbuscular mycorrhizae

Summary Vesicular-arbuscular mycorrhizae on red clover and maize absorbed S³⁵ at higher rates than did comparable nonmycorrhizal roots.Former Research Assistant and Professor, Department of Plant Pathology, University of Illinois, Urbana, Illinois, respectively.     

Multiple temperature optima in collectotrichum graminicola

Summary The dry weights of three isolates ofColletotrichum graminicola (Ces.)Wills., growing at 10°, 15°, 20°, 30°, and 35° C in yeast extract liquid medium were recorded. Two temperature growth optima and minima occurred at 20°C, 30°C and 10°C, 25°C respectively.Portion of a Ph. D. thesis, The Ohio State University, Columbus 10, Ohio, U.S.A. Department of Botany and Plant Pathology. Paper Number 657.     

Measurement of organic-35S and organic-S in lake sediments: Methodological considerations

Three protocols for the determination of inorganic and organic sulfur fractions were tested for their suitability to estimate total indigenous organic sulfur (S_org) and³⁵S_org formed from added³⁵SO₄ ^2– in sediments of chemically dilute lakes in the ELA. The protocols tested have all been reported in the literature. It was found that two protocols involving sequential analyses for S fractions following acid treatment gave estimates of both S_org and³⁵S_org up to 87% lower than a non-sequential protocol. The low estimates were largely due to hydrolysis and solubilization of solid phase S which was then removed in a rinsing step. The non-sequential protocol, in which total reduced inorganic sulfur and total sulfur were determined on separate aliquots, is recommended as the most reliable of the three. Individual analyses in this protocol were verified for these lake sediments using a variety of S standards.     

The epiphytology of spearmint rust in Indiana

Summary Field studies indicated that subterranean aecia ofPuccinia menthae Pers. are of little significance in the initiation of spearmint rust infection in undisturbed fields. Also, wild or escaped mints do not appear to be of significance. The primary source of inoculum comes either from fields that are not fall plowed or from infected rhizomes or transplants during spring planting. Temperatures during May appear to be critical in the development of rust epiphytotics. The predominant race of the pathogen occurring in Indiana corresponds to Race 1.Respectively, former graduate research assistant, Department of Botany and Plant Pathology, Purdue University, presently Assistant Plant Pathologist, University of Arizona, Mesa Branch Experiment Station, Mesa, Arizona; and Associate Plant Pathologist, Department of Botany and Plant Pathology, Purdue University, Lafayette, Indiana. Journal paper 2691. The authors thank Dr.M. J. Murray, A. M. Todd Company, Kalamazoo, Michigan, for species ofMentha used as race differentials. This research was supported, in part, by funds provided through the Mint Industries Research grant.     

Factors influencing pathogenicity of three isolates of colletotrichum graminicola on wheat

Summary Factors such as varieties of wheat, hydrogen ion and various mineral salts concentrations of soil having possible influence on the pathogenicity of certain isolates ofColletotrichum graminicola (Ces.)Wils. on wheat were studied. Of the six varieties of wheat studied, the variety Dual was highly susceptible, and the variety Knox highly resistant. The percentage seedling blight was greatest in soil at the highest pH values, 7.0–9.0. Concentrations of potassium nitrate, ammonium nitrate and magnesium sulfate in soil greatly influenced disease development.Portion of a Ph. D. thesis, Department of Botany and Plant Pathology, The Ohio State University, Columbus-10, Ohio, U.S.A.     

Factors influencing formation of acervuli and conidia by Collectotrichum graminicola

Summary Abundant sporulation of certain isolates ofColletotrichum graminicola (Ces.)Wils., occurred when sufficient aeration was provided to their liquid culture either by reducing the quantity of the media or by forcing air into them. Certain carbon and nitrogen compounds caused more sporulation of only orchard grass isolate of the fungus. When sufficient aeration was provided to the culture media more sporulation also occurred at a temperature range of 20–30°C. Glucose content of the media did not have any influence on sporulation.Portion of a Ph.D. thesis, Department of Botany and Plant Pathology, The Ohio State University, Columbus 10, Ohio, U.S.A.     

Studies on the control of mitotic activity

Summary A tetraploid cell population was produced in the primary root meristem of Pisum sativum by one-half hour treatments with various concentrations of colchicine. The tetraploid population so produced was found to be reasonably synchronous in its passage through successive mitotic cycles with the degree of synchrony being more or less proportional to the concentration of colchicine used. The average time between mitoses appears to be of the order of 12 hours which agrees well with previous estimates. Treatments of roots containing tetraploid populations with 2.52 × 10^–5 M. actidione for 15 minutes were used to demonstrate the possibility of using the system for studies on the differential susceptibility of cells at different stages of the mitotic cycle.This work was carried out under contract number RG-4835 of the National Institutes of Health, United States Public Health Service, and an Institutional Grant from the American Cancer Society.Contribution number 59-26 of the Department of Botany and Plant Pathology, Michigan State University, East Lansing, Michigan.Predoctoral Fellow (CF-9871) of the National Cancer Institute, United States Public Health Service     

Parasitism of monolayer cultures of dog tissue by Histoplasma capsulatum,I preliminary investigations

Summary Monolayer tissue cultures of canine kidney are demonstrated to by susceptible to invasion by yeast-phaseHistoplasma capsulatum. Primary and secondary tissue cultures of canine kidney show different levels of invasion by the pathogen at 24 hours after inoculation; these differences are interpreted as being related to the number of dividing host cells. By 72 hours after inoculation, similar numbers of yeast cells are demonstrable within the host cells of primary and secondary cultures. Essentially identical results were obtained when canine heart tissue cultures were inoculated with y-phaseH. capsulatum.Paper No.713, Department of Botany and Plant Pathology, The Ohio State University, 1735 Neil Avenue, Columbus 10, Ohio; correspondence should be directed to the junior author at the above address.     

In vitro cytokinin binding to a particulate fraction of tobacco cells

At least two types of cytokinin-binding sites are present in a particulate fraction of tobacco (Nicotiana tabacum L.) cells that sediments at 80,000 x g. The major binding component has a low affinity towards cytokinins, is resistant to heating at 100°C, and is not specific for biologically active cytokinin analogues. The second site occurs in much lower frequency, is heat labile, shows high affinity towards cytokinins, and is specific for biologically active analogs of the hormone. The testing for binding specificity was mainly performed with a series of halogenated benzyladenine derivatives having a wide range of biological activities. The low-affinity binding site shows some of the same features as talcum powder, a non-biological material which binds cytokinins in a non-specific fashion. The properties of the high-affinity binding site are consistent with the expected characteristics of a cytokinin receptor. However, the role of the observed high-affinity binding site with regard to the biological action of cytokinins is not yet known.Abbreviations BA N ⁶-benzyladenine - 2,4-D 2,4-dichlorophenoxyacetic acid - IAA indole-3-acetic acid - K_d equilibrium dissociation constant - R_t total concentration of binding sites In partial fulfillment of the requirements for the Ph.D. degree in the Department of Botany and Plant Pathology, Michigan State University     

Variation in the distribution of a genome-specific DNA sequence on chromosomes reveals evolutionary relationships in the Triticum and Aegilops complex

 The present study analyzed the distribution pattern of the Ae. speltoides–derived repetitive clone pGc1R-1 in the Triticum/Aegilops complex. Fluorescence in situ hybridization analysis showed that clone pGc1R-1 is a S-genome-specific repetitive sequence that hybridized to the S-genome of three species in the section Sitopsis, Aegilops speltoides (S), Ae. longissima (S^l), and Ae. sharonensis (S^sh), but not to Ae. bicornis (S^b) and Ae. searsii (S^s), nor to any other diploid Aegilops species. This clone also hybridized to the very closely related G-genome of T. timopheevii subsp. armeniacum and T. timopheevii ssp. timopheevii, but not to the B-genome of T. turgidum and T. aestivum. Hybridization also was observed in the polyploid Aegilops species, Ae. kotschyi (U^kS^k), Ae. peregrina (U^pS^p), and Ae. vavilovii (X^vaD^vaS^va). Large inter- and intraspecific variations were observed. Our results confirm that the S genome is related more to the S^l and S^sh genomes than to the S^b and S^s genomes; there is a greater affinity between the G and S genomes than between the B and S genomes. Mechanisms to account for the variation in the FISH pattern with different genomes include sequence amplification and deletion. Variation in the distribution of this genome-specific DNA sequence, pGc1R-1, on chromosomes can be used to reveal evolutionary relationships in the Triticum and Aegilops complex. Received April 10, 2002; accepted July 12, 2002 Published online: November 28, 2002 Address of the authors: Peng Zhang, Bernd Friebe (e-mail: friebe@ksu.edu), Bikram S. Gill, Wheat Genetics Resource Center, Department of Plant Pathology, 4024 Throckmorton, Plant Sciences Center, Kansas State University, Manhattan, KS 66506-5502, USA.     

The Lack of Selective Reincorporation into Tissue Protein of the Amino Acids Derived from the Catabolism of Serum Protein

Homologous S³⁵-labeled albumin, gamma globulin, and alpha-beta globulin were transfused into rabbits and the specific activities of the electrophoretic fractions of the sera of the recipients were determined at various time intervals up to 12 days after injection. Detectable reincorporation into a fraction other than that transfused was found only in the gamma globulin fraction after albumin injection. This activity rose between 2 and 12 days and reached a level of 2 to 3 per cent of the extrapolated zero time activity of the albumin fraction. When homologous serum protein doubly labeled with I¹³¹ and S³⁵ was transfused into mice, marked drops in the ratios of I¹³¹ to S³⁵ in the serum and tissue proteins were observed between 1 and 48 hours after injection. On the basis of a determination of the absolute and relative amounts of I¹³¹ and S³⁵ found in the various tissue and serum proteins, the amount of reincorporation of S³⁵ into each protein was calculated. The relative amounts of reincorporation of S³⁵ among the various tissues were remarkably similar to the relative amounts of incorporation of S³⁵ after the injection of labeled free amino acids. It is concluded that serum protein does not form a major direct source of amino acids to the tissues but feeds them indirectly through the extracellular pool.     

Plastids of sieve tube members in the stamen vascular bundle ofSorghum bicolor (Gramineae)

Summary The plastids in sieve tube members of the stamen vascular bundles ofSorghum bicolor, fixed in glutaraldehyde with postfixation in osmium tetroxide, are of the P-type containing cuneate crystalloids of a proteinaceous nature surrounded by a double envelope. Secondary inclusions are present in these P-type plastids. P-type plastids inSorghum often remain intact in the mature sieve tube members.This work was supported by a grant from the Iowa Agricultural and Home Economics Experiment Station, Ames, U.S.A. Project No. 1740 toHarry T.Horner, Jr., andNels R.Lersten and Project No. 1914 toHarry T.Horner, Jr. of the Department of Botany and Plant Pathology, Iowa State University, Ames, U.S.A. This work was completed by the author as part of the Ph. D. dissertation research.     

EFFECT OF CARBONYL CYANIDE PHENYLHYDRAZONE ON CATION UPTAKE IN EXCISED BARLEY ROOTS

The generally-accepted characteristics of ion transport in planttissue do not apply completely in the case of zinc uptake. Inthis case, 5x1^–5 M CCP (which completely stops rubidiumuptake in barley roots) shows little inhibitory effect. In thisrespect it is like DNP which also shows little influence onzinc uptake in this concentration. ¹ Present Address: Department of Botany and Plant Pathology,University of Minnesota, St. Paul, Minnesota, U.S.A.     

Variation in susceptibility to experimental dermatomycosis in genetic strains of mice,I. Preliminary studies

Summary Results of a preliminary study of the degree of susceptibility of two inbred mouse strains (C 57 B1/6 and DBA₂) and the F₁ progeny (BDF₁) of these lines are reported. The possible significance of our findings are discussed in respect to the published accounts of the influence of the age, physiological response mechanisms, and immunological defense mechanisms of the suscept host and the age and strain of the fungus and the size of the inoculum. The possibility of theTrichophyton mentagrophytes carriers being animals that had the disease several times in the past, resulting in immunity or a high degree of resistance, is suggested. The results of this study have indicated several technical refinements which will be incorporated into subsequent experiments.Paper No. 665, Department of Botany and Plant Pathology, Ohio State University, 1735 Neil Avenue, Columbus 10, Ohio.The research was performed by the junior authors at the suggestion of and with guidance from the senior author, as part of the requirements for a course in medical mycology in this department.     

Experimental maduromycosis in the laboratory mouse

Summary 1. A 0.5 ml inoculum containing 1.4×10⁴ spores and/or mycelial fragments ofAllescheria boydii when injected intraperitoneally, did not cause death in 18–20 g female Swiss mice in 18 days.2. Focal, pin-point lesions developed in the liver and spleen of mice injected with the stock suspension and the 1:10 dilution of it (2.8×10⁴ and 2.8×10³ infective units ofA. boydii per ml, respectively); no lesions developed from the 1:100 dilution of the original suspension.3.Allescheria boydii was recovered from the livers and spleens of all mice, as well as from the peritoneal exudate of one mouse injected with the stock suspension ofA. boydii; the fungus was not isolated from heart's blood.4. Inability to cause death by the intraperitoneal injection ofA. boydii inocula might be attributed to the natural defense mechanisms in the mice or to the excessive dilution of the inoculum; it is improbable that any genetically controlled resistance to allescheriosis exists in the mice used in this study.Paper no. 664, Department of Botany and Plant Pathology, Ohio State University, 1735 Neil Avenue, Columbus 10, Ohio.This is the report of research done by the junior authors with the guidance of the senior author during a course in medical mycology in this department.     

In vivo regulation of de novo methionine biosynthesis in a higher plant (lemna)

Administration of methionine to growing Lemna had essentially no effect on accumulation of sulfate sulfur in protein cysteine, but decreased accumulation into cystathionine and its products (homocysteine, methionine, S-methylmethioninesulfonium salt, S-adenosylmethionine, and S-adenosylhomocysteine) to as low as 21% that of control plants, suggesting that methionine regulates its own de novo synthesis at cystathionine synthesis. Methionine caused only a slight reduction (to 80% that of control plants) in the accumulation of sucrose carbon into the 4-carbon moieties of cystathionine and products. This observation was puzzling since cystathionine synthesis proceeds by incorporation of equivalent amounts of sulfur (from cysteine) and 4-carbon moieties (from O-phosphohomoserine). The apparent inconsistency was resolved by the demonstration in Lemna (Giovanelli, Datko, Mudd, Thompson 1983 Plant Physiol 71: 319-326) that de novo synthesis of the methionine 4-carbon moiety occurs not only via the established transsulfuration route from O-phosphohomoserine, but also via the ribose moiety of 5′-methylthioadenosine. It is now clear that the more accurate assessment of the flux of sulfur (and 4-carbon moieties) through transsulfuration is provided by the amount of ³⁵S from ³⁵SO₄²⁻ that accumulates in cystathionine and its products, rather than by the corresponding measurements with ¹⁴C. These studies therefore unequivocally demonstrate in higher plants that methionine does indeed feedback regulate it own de novo synthesis in vivo, and that cystathionine synthesis is a locus for this regulation.     

Uptake and distribution of S-sulfate in needles and roots of spruce seedlings as affected by exposure to SO2 and H2S

The interaction between pedospheric and atmospheric sulfur nutrition was studied in seedlings of Norway spruce. Spruce was grown on a 25% Hoagland nutrient solution containing ³⁵S-sulfate and simultaneously exposed to 250 nl l⁻¹ atmospheric SO₂ or H₂S. A 6-day exposure to SO₂ and H₂S resulted in a substantial increase in the total sulfur concentration of the needles. This increase could be ascribed to increased needle concentrations of sulfate, water-soluble non-protein thiols and organic sulfur. SO₂ and H₂S exposure resulted in slight but significant increases in the concentration of sulfur compounds in roots. In all sulfur fractions, except sulfate, there was a substantial decrease in the level of ³⁵S in needle and root sulfur fractions upon SO₂ and H₂S exposure, demonstrating that spruce was able to switch from pedospheric sulfate to atmospheric sulfur as a source for growth. In needles, the amount of ³⁵S decreased in total organic S and glutathione fraction, whereas it increased in sulfate. This supports continued import of S taken up by the roots into the needles in spite of a decreased channeling of ³⁵S into synthesis in needles. A greater part of total sulfate increase was due to unlabeled S, which points towards metabolic oxidation of H₂S and SO₂ to sulfate. Increased concentrations of S compounds (including sulfate) in roots were mainly due to unlabeled S, indicating an import of sulfur from the foliage. The significance of glutathione in the translocation of reduced sulfur from the needles to the roots is discussed.     

Nuclear degeneration in the myxomycetePhysarella oblonga

Summary Nuclear degeneration is a distinct and normal process occurring during sporogenesis in the myxomycete,Physarella oblonga. About 30% of the nuclei present in the developing sporangium abort. Nuclei that undergo degeneration are first surrounded by vacuoles. The membranes of the vacuoles and nuclear envelope are 75 thick. As degeneration progresses the vacuoles fuse resulting in a nucleus surrounded by a single, narrow vacuole. The membrane next to the nucleus degenerates while the membrane adjacent to the sporangial cytoplasm thickens to 100 . Lysosomes then fuse with the vacuole, and digestion of the nucleus begins. The undigested remains of nuclei (residual bodies) are excreted from the protoplast. Acid phosphatase is localized in the lysosomes and degenerating nuclei.A portion of this work was conducted at Department of Botany and Plant Pathology, Iowa State University, Ames.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.