Studies in the eupatorieae (Compositae). XVII. The genus erythradenia (B. L. Robinson) R. M. King and H. Robinson

Piqueria (Erythradenia) pyramidalis B. L. Robinson is placed in a separate genus with the new combinationErythradenia pyramidalis (B. L. Robinson) R. M. King & H. Robinson. It is considered a close relative of the genusDecackaeta DC     

Cytotaxonomic study ofChelidonium majus L. s. l.

The present paper deals with cytotaxonomy ofChelidonium majus L. s. 1. taxa and their hybrids. Based on results of hybridization experiments, cytology and reproductive isolation, a new combination,Ch. asiaticum (Hara) Krahulcová, is proposed. The structure of the aggregate is as follows:Ch. majus L. subsp.Majus (2n=12, distributed in Europe),Ch. majus L. subsp.grandiflorum (DC.)Printz (2n=12, S. Siberia, China) andCh. asisaticum (2n=10, E. Asia). Karyotypes ofCh. m. subsp.grandiflorum andCh. asiaticum are compared in detail.     

First elucidation of a didymozoid life cycle: Saccularina magnacetabula n. gen. n. sp. infecting an arcid bivalve

The first first-intermediate host for a species of Didymozoidae (Trematoda: Hemiuroidea), a bivalve of the family Arcidae, is identified using multi-loci molecular data. First intermediate, (likely) third intermediate, and adult stages of a new didymozoid taxon (Saccularina magnacetabula n. gen. n. sp.) from Moreton Bay, Queensland, Australia were collected from the Sydney cockle Anadara trapezia (Deshayes) (Arcoidea: Arcidae), Sillago sp. (Sillaginidae) and Elops hawaiensis Regan (Elopiformes: Elopidae), respectively, and genetically matched. Infections in A. trapezia were present as sporocysts and cystophorous cercariae, and infected tissue at the base of the gills. Morphologically, S. magnacetabula is distinctive relative to all other didymozoids in the combination of hermaphroditism, mate-pairing, filiform body shape, the presence of a ventral sucker, a single testis, and a saccular excretory vesicle at the posterior extremity. Molecular sequence data were generated for S. magnacetabula and 42 other putative didymozoid species to explore relationships within the Didymozoidae and Hemiuroidea. In molecular phylogenetic analyses of the 28S rDNA region, the new genus forms a clade with an undescribed taxon from the redthroat emperor, Lethrinus miniatus (Bloch & Schneider) (Perciformes: Lethrinidae), from the Great Barrier Reef, and another uncharacterised taxon from E. hawaiensis. This clade is sister to a moderately well-supported clade comprising all other didymozoid species for which sequences are available, including representatives of five of the six presently recognised subfamilies. The infection of a bivalve by a didymozoid is discussed in the context of the overwhelming use of gastropod molluscs as first intermediate hosts by the Hemiuroidea.     

Pleuromeia from the lower triassic of the far east of the U.S.S.R.

Pleuromeia obrutschewii Elias from Russian Island (Russkiy Ostrov, near Vladivostok) is hardly distinguishable from the European P. sternbergii (Muenster) Corda. The sporangia are adaxial, filling spoon-like depressions of the megasporophylls which have sterile tips. P. olenekensis sp. nov. from the Olenek River (northeastern Siberia) has larger sporangia and much larger megaspores with three-layered walls. The outer layer (ectexosporium) is reticulate. It is assumed that in other species this layer is lacking due to imperfect preservation. Mature megasporophylls, when shed, have a buoy-like shape and are often deposited together with cephalopod shells. This suggests a special mechanism of propagation by means of megasporophylls dispersed by water currents. The cosmopolitan distribution of Pleuromeia points to weakened climatic zonation in the Early Triassic.     

Pseudangularia gonzalezi n. sp. and Gibsonilepis swifti (Singh, 1952) n. g., n. comb. (Cestoda, Dilepididae) from the House Swift, Apus affinis (J.E. Gray) (Aves, Apodiformes) from Franceville, Republic of Gabon

Nine specimens of Apus affinis (J.E. Gray) were studied at Franceville, Haut-Ogooué Province, Republic of Gabon, for the presence of helminth parasites. Two cestode species of the family Dilepididae were recorded. Pseudangularia gonzalezi n. sp. is distinguished from the most similar species P. europaea Georgiev & Murai, 1993 by having elliptical cirrus-sac, longer vagina, longer rostellar sheath and greater diameter of suckers. An identification key to the species of the genus Pseudangularia Burt, 1938 is proposed. The present study is the first record of the genus Pseudangularia in the Afrotropical Region. Our study confirms that, in dilepidids with vaginal sclerites from swifts, breaking off the cirrus after copulation is a frequent phenomenon. The genus Gibsonilepis n. g. is erected as monotypic for Vitta swifti Singh, 1952 (originally described from the same host species in India) and Gibsonilepis swifti n. comb. is proposed. Gibsonilepis n. g. is distinguished from Vitta Burt, 1938 by its highly elongate rostellum, rostellar sheath much bigger than rostellum, relatively small rostellar hooks possessing strongly developed guard, disc-shaped suckers with weak peripheral musculature and flat or convex central part, long and well-expressed neck, highly lobed two-winged ovary (lobes rounded) and presence of a band consisting of rows of spine-like microtriches along posterior margin of each proglottis. This is the first record of G. swifti in the Afrotropical Region. The separation of G. swifti from the genus Vitta (parasites of swallows) suggests that, contrary to previous opinions, no dilepidid genera are shared by Apodidae (swifts) and Hirundinidae (swallows).     

New Species of Boletellus Section Boletellus (Boletaceae,Boletales) from Japan,B. aurocontextus sp. nov. and B. areolatus sp. nov.

We describe and illustrate two new species of Boletellus section Boletellus, B. aurocontextus sp. nov. and B. areolatus sp. nov., which are generally assumed to be B. emodensis. In this study, we reconstructed separate molecular phylogenetic trees of section Boletellus using the nucleotide sequences of the internal transcribed spacer (ITS) region of nuclear ribosomal DNA, the largest subunit (RPB1) and the second-largest subunit (RPB2) of nuclear RNA polymerase II gene and mitochondrial cytochrome oxidase subunit 3 (cox3) gene. We also examined the morphologies of B. emodensis sensu lato (s.l.) and other related species for comparison. The molecular phylogenetic tree inferred from the sequences of nuclear DNA (ITS, and combined dataset of RPB1 and RPB2) indicated that three genetically and phylogenetically well-separated lineages were present within B. emodensis s.l. These three lineages were also distinguished on the basis of the molecular phylogenetic tree constructed using the sequences of mitochondrial DNA (cox3), suggesting distinct cytonuclear disequilibria (i.e., evidence of reproductive isolation) among these lineages. Therefore, these three lineages can be treated as independent species: B. aurocontextus, B. areolatus, and B. emodensis. Boletellus aurocontextus and B. areolatus are also distinct from B. emodensis by the macro- and microscopic morphologies. Boletellus aurocontextus is characterized by a pileus with bright yellow to lemon yellow context, which can be observed through a gap in the scales, and basidiospores with relatively large length (mean spore length, 21.4 μm; quotient of spore length and width, 2.51). In contrast, B. areolatus is characterized by a pileus with floccose to appressed thin scaly patches, a stipe with pallid or pale cream color at the upper half, and basidiospores with relatively small length (mean spore length, 16.5 μm; quotient of spore length and width, 1.80).     

Meiosis in Male DROSOPHILA MELANOGASTER. II. Nonrandom Segregation of Compound-Second Chromosomes

The segregation of compound-second chromosomes in males from two different stocks has been examined. Segregation is random in males from the C(2L)RM4, dp; C(2R)RM4, px stock. Gametes containing only one of the two compound chromosomes comprise 50% of the gametes, and gametes containing either both elements or neither element make up the other 50% of the gametes.——In males from the C(2L)RM, b; C(2R)RM, cn stock, gametes containing either C(2L)RM, b or C(2R)RM, cn make up the majority of the gametes. Gametes containing both chromosomes or neither chromosome account for only 2-3% of the gametes. The nonrandom segregation is due to the C(2R)RM, cn chromosome.——Viability is reduced in flies carrying the C(2R)RM, cn chromosome. This includes larval lethality, delayed development and premature adult lethality. Cytologically, this chromosome contains a large duplication of 2L material, which includes material proximal to region 38 or 39. It is suggested that the viability and segregational properties associated with this chromosome are due to the duplicated 2L material.     

Beef liver esterase. II. Kinetic properties

The kinetic parameters, k_cat and K_M, in beef liver esterase-catalyzed hydrolysis were determined for about 100 substrates, which can be classified in several groups: (1) In the ethyl ester series of fatty acids K_M decreases with elongation of the acid, while k_cat has a maximum value with pentanoate. (2) Alkyl acetates are better substrates as the alkyl moiety is longer, whereas esters with branched alkyl groups become worse substrates. (3) Aryl esters are very good substrates. (4) Esters of dicarboxylic acids are good substrates, but only one ester group is cleaved by the enzyme. Fumarate diester is susceptible to esterase hydrolysis, while maleate is not. (5) Esters of hydrophobic amino acids are very good substrates; the enzyme is not stereoselective and both the l and d stereoisomers are readily hydrolyzed. Branching at the β-carbon atom leads to loss of activity, and blocking of the amino group abolishes it. Fluoride ion and dl-malate esters are potent competitive inhibitors of the enzymic reaction. The optimal pH was found to lie between 8 and 8.5. The reaction rate increased between 5 and 40 °C then dropped sharply. The activity decreased at high salt concentration.     

Mesocriconema ornicauda n. sp. and Ogma floridense n. sp. (Nematoda: Criconematidae) from Two Florida Habitats

Mesocriconema ornicauda n. sp. and Ogma floridense n. sp. are described from two native habitats of central and northwestern Florida. Mesocriconema ornicauda is closest to M. annulatiforme (De Grisse &Loof, 1967) Loof &De Grisse, 1989, but differs by the shorter stylet of the female (43-50 vs. 54-65 μm) and the moderately conoid tail of the male, which is pointed in M. annulatiforme. Ogma floridense is closest to O. hungaricum (Andrassy, 1972) Siddiqi, 1986. Females differ from those of O. hungaricum by the first of two labial annuli being wider, whereas they are subequal in O. hungaricum. Ogma floridense females differ also by entire or bifid cuticular scales, which are consistently divided into two or four projections in O. hungaricum, the shorter body (360-471 vs. 480-550 μm), the shorter stylet (87-98 vs. 95-100 μm), and the more anteriorly located excretory pore (Rex = 17-19 vs. 21-23).     

Morphology and phylogeny of Bryophryoides ocellatus n. g., n. sp. (Ciliophora,Colpodea) from in situ soil percolates of Idaho,U.S.A.

We describe the morphology and 18S rDNA phylogeny of Bryophryoides ocellatus n. g., n. sp., a bryophryid ciliate inhabiting in situ soil percolates from Idaho, U.S.A. The new genus is distinguished from other bryophryid genera by a combination of the following features: (1) kreyellid (irregularly meshed) silverline pattern, (2) polymorphic adoral organelles in the preoral suture, (3) absence of vestibular kineties. In phylogenetic analyses, Bryophryoides ocellatus is most closely related to Bryophrya gemmea. The 18S rDNA sequence pairwise distance of 2% between these genera, while similar to that between many colpodidan species, exceeds that between some colpodidan genera (e.g. Mykophagophrys and Pseudoplatyophrya, 1.1%), further supporting establishment of the new genus. Topology hypothesis testing strongly supports the monophyly of the Colpodida including the bryophryids. Despite weak nodal support, tests of topology constraints narrowly reject the non-monophyly of the sequenced Bryophryidae (Bryophrya + Bryophryoides + Notoxoma). Likewise, the monophyletic origin of the sequenced Bryophryidae is indicated in the phylogenetic networks though with low support.     

Dr. Horace S. Isbell

Addition of ethyl isocyanoacetate in strongly basic medium to the glycosuloses 1,2:5,6-di-O-isopropylidene-α-d-ribo-hexofuranos-3-ulose (1) and 1,2-O-isopropylidene-5-O-trityl-d-erythro-pentos-3-ulose (2) gave the unsaturated derivatives (E)- and (Z)-3-deoxy-3-C-ethoxycarbonyl(formylamino)methylene-1,2:5,6-di-O-isopropylidene-α-d-glucofuranose (3 and 4), and (E)-3-deoxy-3-C-ethoxycarbonyl(formylamino)methylene-1,2-O-isopropylidene-5-O-trityl-α-d-ribofuranose (5). In weakly basic medium, ethyl isocyanoacetate and 1 gave 3-C-ethoxycarbonyl(formylamino)methyl-1,2:5,6-di-O-isopropylidene-α-d-allofuranose (12) in good yield. The oxidation of 3 and 4 with osmium tetraoxide to 3-C-ethoxalyl-1,2:5,6-di-O-isopropylidene-α-d-glucofuranose (17), and its subsequent reduction to 3-C-(R)-1′,2′-dihydroxyethyl-1,2:5,6-di-O-isopropylidene-α-d-glucofuranose (18) and its (S) epimer (19) and to 3-C-(R)-ethoxycarbonyl(hydroxy)methyl-1,2:5,6-di-O-isopropylidene-α-d-glucofuranose (21) and its (S) epimer (22) are described. Hydride reductions of 12 yielded the corresponding 3-C-(1-formylamino-2-hydroxyethyl), 3-C-(2-hydroxy-1-methylaminoethyl), and 3-C-(R)-ethoxycarbonyl(methylamino)methyl derivatives (13, 14 and 16). Catalytic reduction of 3 and 4 yielded the 3-deoxy-3-C-(R)-ethoxycarbonyl-(formylamino)methyl derivative 6 and its 3-C-(S) epimer. Further reduction of 6 gave 3-deoxy-3-C-(R)-(1-formylamino-2-hydroxyethyl)-1,2:5,6-di-O-isopropylidene-α-d-allofuranose (23) which was deformylated with hydrazine acetate to 3-C-(R)-(1-amino-2-hydroxyethyl)-3-deoxy-1,2:5,6-di-O-isopropylidene-α-d-allofuranose (24). The configurations of the branched-chains in 16, 21, and 22 were determined by o.r.d.     

Species composition and toxicity of the genus Pseudo-nitzschia in Taiwan Strait,including P. chiniana sp. nov. and P. qiana sp. nov.

In a field survey in the Taiwan Strait during April 2016, the species composition and the domoic acid production of the diatom genus Pseudo-nitzschia were investigated. A total of 80 strains of Pseudo-nitzschia were established, and species identification was determined based on a combination of morphological and molecular data. Fourteen taxa were recognized, i.e., P. americana, P. brasiliana, P. calliantha, P. cuspidata, P. galaxiae, P. lundholmiae, P. multiseries, P. multistriata, P. pseudodelicatissima, P. pungens var. aveirensis, P. pungenus var. pungens and P. sabit, as well as two novel species P. chiniana C.X. Huang & Yang Li and P. qiana C.X. Huang & Yang Li. Morphologically, P. chiniana is characterized by striae comprising one or two rows of poroids, and valve ends that are normally dominated by two rows of poroids within each stria. Whereas P. qiana is unique by having a narrow valve width (1.3–1.5 μm) and sharply pointed valve ends. Both taxa constitute their own monophyletic lineage in the phylogenetic analyses inferred from LSU and ITS2 rDNA, and are well differentiated from other Pseudo-nitzschia species. Pseudo-nitzschia chiniana forms a group with P. abrensis and P. batesiana in LSU and ITS trees, whereas P. qiana is sister to P. lineola. When comparing ITS2 secondary structure, five CBCs and seven HCBCs are recognized between P. chiniana and P. abrensis, and four CBCs and ten HCBCs between P. chiniana and P. batesiana. Two CBCs and eight HCBCs are found between P. qiana with P. lineola. The ability of the strains to produce domoic acid was assessed, including a potential toxin induction by the presence of brine shrimps. Results revealed production of domoic acid in six strains belonging to three species. Without presence of brine shrimps, cellular DA (pDA) was detected in four P. multiseries strains (1.6 ± 0.3, 26.6 ± 2.7, 68.3 ± 4.2 and 56.9 ± 4.7 fg cell⁻¹, separately), one strain of P. pseudodelicatissima (0.8 ± 0.2 fg cell⁻¹) and one strain of P. lundholmiae (2.5 ± 0.4 fg cell⁻¹). In the presence of brine shrimps, pDA contents increased significantly (p < 0.05) in P. lundholmiae (strain MC4218) and P. multiseries (strain MC4177), from 2.5 ± 0.4 to 8.9 ± 0.7 and 1.6 ± 0.3 to 37.2 ± 2.5 fg cell⁻¹ respectively.     

Electron transfer between the two photosystems. II. Equilibrium constants

(1) The equilibrium constants for the redox reactions occurring between Photosystem (PS) I donors were measured on chloroplasts, dark-adapted in the presence of sodium ascorbate and 3-(3′,4′-dichlorophenyl)-1,1-dimethylurea (DCMU) and then illuminated by d.c. light. The equilibrium constant for the electron transfer between plastocyanin and P-700 is close to 1 and the overall equilibrium constant between cytochrome f and P-700 is about 2.3. As these equilibrium constants do not depend upon the intensity of the d.c. beam, the low values we measured cannot be due to kinetic limitations. (2) The equilibrium constants were measured also in the absence of DCMU using chloroplasts in oxidizing conditions (ferricyanide or far red illumination) illuminated by a saturating flash. During the course of the reduction of PS I donors by plastoquinol molecules formed by the flash, the equilibrium constants are higher than in the preceding conditions: the value for plastocyanin to P-700 is close to 5, and that for cytochrome f to P-700 is about 25. (3) The variations of these equilibrium constants are tentatively interpreted as being due to mutual electrostatic interactions between cytochrome b and f which are included in the same complex. This model implies that the perturbation of the redox properties of cytochrome f by a positive charge located on cytochrome b is identical to the perturbation of the redox properties of cytochrome b by a positive charge located on cytochrome f.     

Hydrolytic enzyme substrates. 3. Phosphomonoesterase substrates

This report documents the use of a new and sensitive colorimetric method for measuring phosphomonoesterase activity. The substrates are the phosphate esters of 4-(p-nitrophenoxy)-1,2-butanediol (PNB), 4-(2,4-dinitrophenoxy)-1,2-butanediol (DNB) and 3-(p-nitrophenoxy)-1,2-propanediol (PNG). The key intermediate in the assay is the nitrophenoxy diol which is obtained by enzyme hydrolysis of its phosphate ester. Periodate oxidation of this substance in solution containing methylamine quantitatively yields its nitrophenolate ion whose concentration is determined colorimetrically. The amount of nitrophenolate ion is thus equivalent to the amount of nitrophenoxy diol whose concentration is a function of the phosphomonoesterase activity in the assay sample. The unhydrolyzed phosphomonoester is completely stable to periodate and the hydrolytic conditions used in the assay. The enzymes used to test the substrates were E. coli alkaline phosphomonoesterase and wheat germ phosphomonoesterase. These new esters were all better substrates than the glycerol phosphate esters. Their Michaelis-Menten constants were determined for E. coli phosphomonoesterase.     

DNA intermediates at the Escherichia coli replication fork. II. Studies using dut and ung mutants in vitro.

The incorporation of uracil into and excision from DNA were studied in vitro using lysates on cellophane discs made from Escherichia coli strains with defects in the enzymes dUTPase (dut) and uracil-DNA glycosylase (ung).Results with dut ung lysates indicate that dUTP is competitively incorporated with dTTP at the replication fork. Such incorporation is not due to DNA polymerase I. There is a mild discrimination (2.5-fold) against incorporation of dUTP versus dTTP. These data, together with in vivo uracil incorporation data (Tye et al., 1978) permit a rough estimate of the pool of dUTP in vivo (~0.5% of the dTTP pool).These in vitro data indicate that uracil-DNA glycosylase is the initial step in at least 90% of uracil excision events. However, in a strain defective in uracil-DNA glycosylase (ung-1), uracil-containing DNA is still more subject to single-strand scission than non-uracil-containing DNA, albeit at a rate at least tenfold less than in an ung⁺ strain.A number of qualitative statements may also be made about different steps in uracil incorporation and subsequent excision and repair events. When high levels of dUTP are added in vitro, a dut ung⁺ strain has a higher steady-state level of uracil in newly synthesized DNA than does an isogenic dut⁺ ung strain. Thus the dUTPase in these lysates has a higher capacity to be overloaded than does the excision system (i.e. uracil DNA glycosylase). However, the DNA sealing system (presumably DNA polymerase I and DNA ligase) apparently can handle all single-strand interruptions being introduced by uracil excision at the maximal rate, at least so that DNA synthesis can continue.     

Secondary metabolites from Scutellaria albida L. ssp. velenovskyi (Rech. f.) Greuter & Burdet

Fourteen compounds (Fig.1) were isolated from the aerial parts of Scutellaria albida L. ssp. velenovskyi (Rech. f.) Greuter & Burdet, including four iridoids (1–4) catalpol, macfadienoside, mussaenosidic acid, albidoside; four flavonoids (5–8) hispidulin 7-Ο-β-D-glucuronide, scutellarin, xanthomicrol, eriodictyol; four phenylethanoid glycosides (9–12) verbascoside, leucosceptoside A, martynoside, 2-(3-hydroxy-4-methoxy-phenyl)-ethyl-1-Ο-β-D-glucopyranoside; the sugar ester 6′-β-D-glucopyranosyl-E-p-coumarate (13), as well as the acetogenic glucoside (Z)-3-hexenyl-1-O-β-D-glucopyranosyl-(1 → 2)-β-D-glucopyranoside (14). The structures of the isolates were established by means of NMR and HRMS spectral analyses. This is the first phytochemical study on S. velenovskyi and the first report of an acetogenic glycoside in the genus Scutellaria L. A chemical review on the isolated secondary metabolites in this study has been carried out. The chemotaxonomic value of the isolates is also discussed. Based on the literature data, the analysis revealed that the chemical profile of S. velenovskyi is close to that of the taxa belonging to the S. albida group.     

Host--virus interactions in the control of T4 prereplicative transcription. I. tabC (rho) mutants.

In this paper we describe properties of old (Takahashi, 1978) and new tabC^ts and tabC^cs bacterial mutants. We find that under non-permissive conditions they differently inhibit the synthesis of specific T4 prereplicative gene products. Among such products, that we have been able to identify, are P43 and PrIIA. In contrast, P32 and PrIIB are not affected.Inhibition of P43 (T4 DNA polymerase) synthesis is sufficient to account for depressed DNA synthesis in tabC (Takahashi, 1978).In heterodiploids: (1) all tabC mutants are recessive; (2) all tabC mutants do not complement with each other; (3) at least one, tabC^ts-5521, becomes dominant at 42.6 °C if rho mutant ts15 (Tab⁺) (Das et al., 1976) is situated in trans; (4) tabC^ts-5521 also becomes dominant at 42.6 °C if tabC^cs-110 and tabC^cs-18 are situated in trans (42.6 °C is non-permissive for T4 development on tabC^cs-5521 and permissive for T4 development on tabC^cs mutants).We discuss the possibility that in tabC mutants rho protein is altered and insensitive to T4-specific anti-termination functions. We also discuss a model that accounts for the differential effect of tabC mutants on the synthesis of T4 prereplicative proteins.     

Detoxification of Benzoxazolinone Allelochemicals from Wheat by Gaeumannomyces graminis var. tritici, G. graminis var. graminis, G. graminis var. avenae, and Fusarium culmorum

The ability of phytopathogenic fungi to overcome the chemical defense barriers of their host plants is of great importance for fungal pathogenicity. We studied the role of cyclic hydroxamic acids and their related benzoxazolinones in plant interactions with pathogenic fungi. We identified species-dependent differences in the abilities of Gaeumannomyces graminis var. tritici, Gaeumannomyces graminis var. graminis, Gaeumannomyces graminis var. avenae, and Fusarium culmorum to detoxify these allelochemicals of gramineous plants. The G. graminis var. graminis isolate degraded benzoxazolin-2(3H)-one (BOA) and 6-methoxy-benzoxazolin-2(3H)-one (MBOA) more efficiently than did G. graminis var. tritici and G. graminis var. avenae. F. culmorum degraded BOA but not MBOA. N-(2-Hydroxyphenyl)-malonamic acid and N-(2-hydroxy-4-methoxyphenyl)-malonamic acid were the primary G. graminis var. graminis and G. graminis var. tritici metabolites of BOA and MBOA, respectively, as well as of the related cyclic hydroxamic acids. 2-Amino-3H-phenoxazin-3-one was identified as an additional G. graminis var. tritici metabolite of BOA. No metabolite accumulation was detected for G. graminis var. avenae and F. culmorum by high-pressure liquid chromatography. The mycelial growth of the pathogenic fungi was inhibited more by BOA and MBOA than by their related fungal metabolites. The tolerance of Gaeumannomyces spp. for benzoxazolinone compounds is correlated with their detoxification ability. The ability of Gaeumannomyces isolates to cause root rot symptoms in wheat (cultivars Rektor and Astron) parallels their potential to degrade wheat allelochemicals to nontoxic compounds.     

Genomic Markers for Differentiation of Francisella tularensis subsp. tularensis A.I and A.II Strains

Tularemia is caused by two subspecies of Francisella tularensis, F. tularensis subsp. tularensis (type A) and F. tularensis subsp. holarctica (type B). F. tularensis subsp. tularensis is further subdivided into two genetically distinct populations (A.I and A.II) that differ with respect to geographical location, anatomical source of recovered isolates, and disease outcome. Using two human clinical isolates, suppression subtractive hybridization was performed to identify 13 genomic regions of difference between A.I and A.II strains. Two PCR assays, one to identify A.I and A.II as well as to discriminate between F. tularensis subsp. holarctica and F. novicida and another specific for A.I, were developed. This is the first report to identify and characterize conserved genomic differences between A.I and A.II.