Two closely related pathways of nicotine catabolism in <Emphasis Type="Italic">Arthrobacter nicotinovorans</Emphasis> and <Emphasis Type="Italic">Nocardioides</Emphasis> sp. strain JS614

A virtually identical nicotine catabolic pathway including the heterotrimeric molybdenum enzyme nicotine and 6-hydroxy-pseudo-oxynicotine dehydrogenase, 6-hydroxy-l-nicotine oxidase, 2,6-dihydroxy-pseudo-oxynicotine hydrolase, and 2,6-dihydroxypyridine hydroxylase have been identified in A. nicotinovorans and Nocardioides sp. JS614. Enzymes catalyzing the same reactions and similar protein antigens were detected in the extracts of the two microorganisms. Nicotine blue and methylamine, two end products of nicotine catabolism were detected in the growth medium of both bacterial species. Nicotine catabolic genes are clustered on pAO1 in A. nicotinovorans, but located chromosomally in Nocardioides sp. JS614.     

Isopropanol and acetone induces vinyl chloride degradation in<Emphasis Type="Italic"> Rhodococcus rhodochrous</Emphasis>

In situ bioremediation of vinyl chloride (VC)-contaminated waste sites requires a microorganism capable of degrading VC. While propane will induce an oxygenase to accomplish this goal, its use as a primary substrate in bioremediation is complicated by its flammability and low water solubility. This study demonstrates that two degradation products of propane, isoproponal and acetone, can induce the enzymes in Rhodococcus rhodochrous that degrade VC. Additionally, a reasonable number of cells for bioremediation can be grown on conventional solid bacteriological media (nutrient agar, tryptic soy agar, plate count agar) in an average microbiological laboratory and then induced to produce the necessary enzymes by incubation of a resting cell suspension with isopropanol or acetone. Since acetone is more volatile than isopropanol and has other undesirable characteristics, isopropanol is the inducer of choice. It offers a non-toxic, water-soluble, relatively inexpensive alternative to propane for in situ bioremediation of waste sites contaminated with VC.     

Biotransformation of polychlorinated dibenzo-<Emphasis Type="Italic">p</Emphasis>-dioxin by <Emphasis Type="Italic">Coprinellus</Emphasis> species

A degradation experiment on dibenzo-p-dioxin (DD) and 2,7-dichlorodibenzo-p-dioxin (2,7-DCDD) was carried out using basidiomycetous fungi belonging to the genera Coprinus, Coprinellus, and Coprinopsis. Some species showed a high rate of decrease in DD for the 2-week test period. Among them, Coprinellus disseminatus showed the highest ability to decrease the DD level, close to 100% by the end of 2 weeks. Further examination showed that Coprinellus disseminatus and Coprinellus micaceus, belonging to the genus Coprinellus, were able to metabolize 2,7-DCDD to a monohydroxylated compound, probably mediated by the P450 system. The metabolism of chlorinated DD by fungi capable of living in soil conditions is reported here for the first time.     

Detection of "<Emphasis Type="Italic">Rickettsia</Emphasis> sp. strain Uilenbergi" and "<Emphasis Type="Italic">Rickettsia</Emphasis> sp. strain Davousti" in <Emphasis Type="Italic">Amblyomma tholloni</Emphasis> ticks from elephants in Africa

Background  

To date, 6 tick-borne rickettsiae pathogenic for humans are known to occur in Africa and 4 of them were first identified in ticks before being recognized as human pathogens.     

<Emphasis Type="Italic">Ty</Emphasis>1<Emphasis Type="Italic">/copia</Emphasis>- and <Emphasis Type="Italic">Ty</Emphasis>3<Emphasis Type="Italic">/gypsy</Emphasis>-like DNA sequences in <Emphasis Type="Italic">Helianthus </Emphasis>species

Two repeated DNA sequences isolated from a partial genomic DNA library of Helianthus annuus, p HaS13 and p HaS211, were shown to represent portions of the int gene of a Ty3 /gypsy retroelement and of the RNase-Hgene of a Ty1 /copia retroelement, respectively. Southern blotting patterns obtained by hybridizing the two probes to BglII- or DraI-digested genomic DNA from different Helianthus species showed p HaS13 and p HaS211 were parts of dispersed repeats at least 8 and 7 kb in length, respectively, that were conserved in all species studied. Comparable hybridization patterns were obtained in all species with p HaS13. By contrast, the patterns obtained by hybridizing p HaS211 clearly differentiated annual species from perennials. The frequencies of p HaS13- and p HaS211-related sequences in different species were 4.3x10(4)-1.3x10(5) copies and 9.9x10(2)-8.1x10(3) copies per picogram of DNA, respectively. The frequency of p HaS13-related sequences varied widely within annual species, while no significant difference was observed among perennial species. Conversely, the frequency variation of p HaS211-related sequences was as large within annual species as within perennials. Sequences of both families were found to be dispersed along the length of all chromosomes in all species studied. However, Ty3 /gypsy-like sequences were localized preferentially at the centromeric regions, whereas Ty1/ copia-like sequences were less represented or absent around the centromeres and plentiful at the chromosome ends. These findings suggest that the two sequence families played a role in Helianthusgenome evolution and species divergence, evolved independently in the same genomic backgrounds and in annual or perennial species, and acquired different possible functions in the host genomes.     

Taxonomic characterization of <Emphasis Type="Italic">Haloferax</Emphasis> sp. ("<Emphasis Type="Italic">H. alicantei</Emphasis>") strain Aa 2.2: description of <Emphasis Type="Italic">Haloferax lucentensis</Emphasis> sp. nov.

An extremely halophilic archaeon, previously named as Haloferax sp. strain Aa 2.2 or "Haloferax alicantei" that has been extensively used for genetic studies with halobacteria, was taxonomically characterized by using phenotypic tests (including morphological, physiological, biochemical and nutritional features), DNA-DNA hybridization and 16S rRNA sequence phylogenetic analysis. This organism was isolated in 1986 by Torreblanca et al. from a pond of a Spanish saltern located in Alicante. The cells were pleomorphic, Gram negative and grew optimally at 25% NaCl. The polar lipid composition was similar to that of species of the genus Haloferax. The DNA G+C content of this strain was 64.5 mol%. Phylogenetic analysis based on 16S rRNA sequence comparison confirmed that this archaeon is a member of the genus Haloferax and was most closely related to Haloferax volcanii. DNA-DNA hybridization between strain Aa 2.2 and the type strain of all named species of the genus Haloferax revealed low levels of relatedness (25-2%), supporting the placement of this organism in a new species. On the basis of the phenotypic characteristics, molecular data and phylogenetic analysis we propose to name strain Aa 2.2 as a new species, Haloferax lucentensis sp. nov. The type strain is Aa 2.2 (=JCM 9276=NCIMB 13854=CIP 107410=DSM 14919=CECT 5871=CCM 7023).     

Characterization of a putative fusogen encoded in a mitochondrial plasmid of <Emphasis Type="Italic">Physarum</Emphasis><Emphasis Type="Italic">polycephalum</Emphasis>

The mitochondrial plasmid mF induces mitochondrial fusion in zygotes and during sporulation in the true slime mold Physarum polycephalum. There are nine open reading frames (ORFs) in the mF plasmid, and it has been suggested that ORF640 encodes the mitochondrial fusogen. We prepared antisera directed against the ORF640 protein (ORF640p) in rabbits, and used it to localize this protein in mitochondria. Western blot analysis showed that ORF640p was produced only in the mitochondria of mF⁺ strains, i.e., in cells that carried the mF plasmid. Proteinase K treatment of mitochondria isolated from the mF⁺ strain suggested that the C-terminus coiled-coil (CC) region of ORF640p was exported from the matrix to the cytosol. Digitonin treatment confirmed this localization. West-Western blot analysis suggested that the CC region of ORF640p formed multimers and could interfere with an unknown mitochondrial protein in normal mitochondria. These results suggest that ORF640p is related to fusion of the outer mitochondrial membrane. Electronic Publication     

Mercury Tolerance of Thermophilic <Emphasis Type="Italic">Bacillus</Emphasis> sp. and <Emphasis Type="Italic">Ureibacillus</Emphasis> sp

Although resistance of microorganisms to Hg(II) salts has been widely investigated and resistant strains have been reported from many eubacterial genera, there are few reports of mercuric ion resistance in extremophilic microorganisms. Moderately thermophilic mercury resistant bacteria were selected by growth at 62 °C on Luria agar containing HgCl₂. Sequence analysis of 16S rRNA genes of two isolates showed the closest matches to be with Bacillus pallidus and Ureibacillus thermosphaericus. Minimum inhibitory concentration (MIC) values for HgCl₂ were 80 μg/ml and 30 μg/ml for these isolates, respectively, compared to 10 μg/ml for B. pallidus H12 DSM3670, a mercury-sensitive control. The best-characterised mercury-resistant Bacillus strain, B. cereus RC607, had an MIC of 60 μg/ml. The new isolates had negligible mercuric reductase activity but removed Hg from the medium by the formation of a black precipitate, identified as HgS by X-ray powder diffraction analysis. No volatile H₂S was detected in the headspace of cultures in the absence or presence of Hg²⁺, and it is suggested that a new mechanism of Hg tolerance, based on the production of non-volatile thiol species, may have potential for decontamination of solutions containing Hg²⁺ without production of toxic volatile H₂S.     

<Emphasis Type="Italic">Kretzschmaria varians</Emphasis> sp. nov., <Emphasis Type="Italic">Xylaria coremiifera</Emphasis> sp. nov. and <Emphasis Type="Italic">Xylaria umbonata</Emphasis> sp. nov. from Costa Rica

Kretzschmaria varians, a species apparently related to K. micropus, is described as new. It is distinguished primarily by having asci with 2 to 8 ascospores with inconstant germination slit length and remains of synnemata on stromata and surrounding substrate. Xylaria coremiifera, described here as new, bears small fragile coremia on pulvinate stromata and the surrounding substrate. Asci often have fewer than 8 ascospores, most frequently 4. Xylaria umbonata, described here as new, produces perithecia around a central umbo that appears to be the remains of a synnema. Ascospores have long spiralling germination slits.     

Phylogenetic analyses of <Emphasis Type="Italic">Uromyces viciae-fabae</Emphasis> and its varieties on <Emphasis Type="Italic">Vicia</Emphasis>, <Emphasis Type="Italic">Lathyrus</Emphasis>, and <Emphasis Type="Italic">Pisum</Emphasis> in Japan

A pea rust fungus, Uromyces viciae-fabae, has been classified into two varieties, var. viciae-fabae and var. orobi, based on differences in urediniospore wall thickness and putative host specificity in Japan. In principal component analyses, morphological features of urediniospores and teliospores of 94 rust specimens from Vicia, Lathyrus, and Pisum did not show definite host-specific morphological groups. In molecular analyses, 23 Uromyces specimens from Vicia, Lathyrus, and Pisum formed a single genetic clade based on D1/D2 and ITS regions. Four isolates of U. viciae-fabae from V. cracca and V. unijuga could infect and sporulate on P. sativum. These results suggest that U. viciae-fabae populations on different host plants are not biologically differentiated into groups that can be recognized as varieties.Contribution no. 184, Laboratory of Plant Parasitic Mycology, Institute of Agriculture and Forestry, University of Tsukuba, Japan     

Role of trehalose synthesis pathways in salt tolerance mechanism of <Emphasis Type="Italic">Rhodobacter sphaeroides</Emphasis> f. sp. <Emphasis Type="Italic">denitrificans</Emphasis> IL106

Two strains of trichloroethylene (TCE)-degrading bacteria were isolated from soils at polluted and unpolluted sites. The isolates, strains TE26^T and K6, showed co-substrate-independent TCE-degrading activity. TCE degradation was accelerated by preincubation with tetrachloroethylene, cis-dichloroethylene (DCE) and 1,1-DCE. TCE-degrading activities of strains TE26^T and K6 were 0.23, 0.24 mol min^–1 g^–1 dry cells, respectively. 16S rDNA sequences of strains TE26^T and K6 were almost identical (99.7% similarity), and most closely related to Ralstonia basilensis (ATCC17697^T) (98.5% similarity). From the results of DNA–DNA hybridizations, strain TE26^T was genetically coherent to strain K6 (94 and 88% hybridization), and exhibited lower relatedness to R. basilensis (DSM11853^T) (44% and 15%). In addition, because of the differences in chemotaxonomic properties, strain TE26^T and strain K6 appear to be distinct from all established species of the Ralstonia group. Based on these results and the proposal of transferring R. basilensis and related species to Wautersia gen. nov., we propose that these strains should be assigned to the genus Wautersia as Wautersia numadzuensis sp. nov.     

Biodegradation of malathion by <Emphasis Type="Italic">Brevibacillus</Emphasis> sp. strain KB2 and <Emphasis Type="Italic">Bacillus cereus</Emphasis> strain PU

We report here the degradation of a pesticide, malathion, by Brevibacillus sp. strain KB2 and Bacillus cereus strain PU, isolated from soil samples collected from malathion contaminated field and an army firing range respectively. Both the strains were cultured in the presence of malathion under aerobic and energy-limiting conditions. Both strains grew well in the medium having malathion concentration up to 0.15%. Reverse phase HPLC–UV analysis indicated that Strain KB2 was able to degrade 72.20% of malaoxon (an analogue of malathion) and 36.22% of malathion, while strain PU degraded 87.40% of malaoxon and 49.31% of malathion, after 7 days of incubation. The metabolites mal-monocarboxylic acid and mal-dicarboxylic acid were identified by Gas chromatography/mass spectrometry. The factors affecting biodegradation efficiency were investigated and effect of malathion concentration on degradation rate was also determined. The strain was analyzed for carboxylesterase activity and maximum activity 210 ± 2.5 U ml⁻¹ and 270 U ± 2.7 ml⁻¹ was observed for strains KB2 and PU, respectively. Cloning and sequencing of putative malathion degrading carboxylesterase gene was done using primers based PCR approach.     

Biosynthesis of silver nanoparticles by a new strain of <Emphasis Type="Italic">Streptomyces</Emphasis> sp. compared with <Emphasis Type="Italic">Aspergillus</Emphasis><Emphasis Type="Italic">fumigatus</Emphasis>

Locally isolated strains of a thermoalkalotolerant Streptomyces sp. and Aspergillus fumigatus were used for the in vitro biosynthesis of silver nanoparticles from AgNO₃ solutions. An autolysed cell-free culture filtrate from each strain was used, indicating that the formation mechanism depends on intra-cellular components for both organisms, since culture broths had no significant nanoparticle formation potential. Nanoparticle formation was indicated by a change of the solution from colourless or light brown to dark brown after 24 h or more, and UV–visible spectroscopy and x-ray diffraction analysis confirmed the formation by both organisms. The initial formation kinetics were faster with Aspergillus, but formation continued for a longer period with Streptomyces, resulting in higher concentrations after 48 h. Transmission electron microscope images revealed well dispersed nanoparticles with diameters ranging from 15 to 45 nm from A. fumigatus, while those from Streptomyces sp. had a narrower size distribution of 15–25 nm. The higher productivity and preferred narrower size distribution of Streptomyces, together with its well established industrial use, may make it the preferred choice for further optimization studies.     

<Emphasis Type="Italic">Quinua</Emphasis> and Relatives (<Emphasis Type="Italic">Chenopodium</Emphasis> sect.<Emphasis Type="Italic">Chenopodium</Emphasis> subsect.<Emphasis Type="Italic">Celluloid</Emphasis>)

Traditionally viewed as an Andean grain crop,Chenopodium quinoa Willd. includes domesticated populations that are not Andean, and Andean populations that are not domesticated. Comparative analysis of leaf morphology and allozyme frequencies have demonstrated that Andean populations, both domesticated(quinua) and free-living(ajara), represent an exceptionally homogeneous unit that is well differentiated from allied domesticates of coastal Chile(quingua) and freeliving populations of the Argentine lowlands(C. hircinum). This pattern of relationships indicates that Andean populations represent a monophyletic crop/weed system that has possibly developed through cyclic differentiation (natural vs. human selection) and introgressive hybridization. Relative levels of variation suggest that this complex originated in the southern Andes, possibly from wild types allied withC. hircinum, with subsequent dispersal north to Colombia and south to the Chilean coast. Coastal populations were apparently isolated from post-dispersal differentiation and homogenization that occurred in the Andes. Other data point toward a center of origin in the northern Andes with secondary centers of genetic diversity subsequently developing in the southern Andes and the plains of Argentina. Comparative linkage of South American taxa, all tetraploid, with North American tetraploids of the subsection will eventually clarify this problem. While the possibility of a direct phyletic connection betweenC. quinoa and the Mexican domesticate(C. berlandieri subsp. nuttalliae,) cannot be excluded, available evidence indicates that the latter represents an autonomous lineage that is associated with the basal tetraploid, C. b. subsp.berlandieri, through var.sinuatum, whereas South American taxa show possible affinities to either var. zschackei or var.berlandieri. An extinct domesticate of eastern North America,C. b. subsp.jonesianum, represents either another instance of independent domestication, possibly from subsp. b. var.zschackei, or a northeastern outlier of subsp.nuttalliae.     

<Emphasis Type="Italic">Galleria</Emphasis><Emphasis Type="Italic">mellonella</Emphasis> are Resistant to <Emphasis Type="Italic">Pneumocystis</Emphasis><Emphasis Type="Italic">murina</Emphasis> Infection

Studying Pneumocystis has proven to be a challenge from the perspective of propagating a significant amount of the pathogen in a facile manner. The study of several fungal pathogens has been aided by the use of invertebrate model hosts. Our efforts to infect the invertebrate larvae Galleria mellonella with Pneumocystis proved futile since P. murina neither caused disease nor was able to proliferate within G. mellonella. It did, however, show that the pathogen could be rapidly cleared from the host.     

Revision of the <Emphasis Type="Italic">Serrulati</Emphasis> species of <Emphasis Type="Italic">Penstemon</Emphasis> section <Emphasis Type="Italic">Saccanthera</Emphasis> subsection <Emphasis Type="Italic">Serrulati</Emphasis>

A revision of Penstemon sect. Saccanthera subsect. Serrulati includes a new species (P. salmonensis), a new variety (P. triphyllus var. infernalis), and the elevation of a subspecies to species (P. curtiflorus), bringing the total number of species to eight, which are keyed and described, complete with nomenclature and type citations.