Effect of organic and conventional farming on soil bacterial diversity of pecan tree (Carya illinoensis K. Kosh) orchard across two phenological stages

We described the bacterial diversity of walnut grove soils under organic and conventional farming. The bacterial communities of rhizospheric and nonrhizospheric soils of pecan tree (Carya illinoensis K. Koch) were compared considering two phenological stages (sprouting and ripening). Sixteen operational taxonomic units (OTUs) were identified significantly more abundant according to the plant development, only one according to the farming condition, and none according to the soil origin. The OTUs specificaly abundant according to plant development included Actinobateria (2) and Betaproteobacteria (1) related OTUs more abundant at the sprouting stage, while at the fruit ripening (FR) stage the more abundant OTUs were related to Actinobacteria (6), Alphaproteobacteria (6), and unclassified Bacteria (1). The Gaiellaceae OTU18 (Actinobacteria) was more abundant under conventional farming. Thus, our study revealed that the plant development stage was the main factor shaping the bacterial community structure, while less influence was noticed for the farming condition. The bacterial communities exhibited specific metabolic capacities, a large range of carbon sources being used at the FR stage. The identified OTUs specifically more abundant represent indicators providing useful information on soil condition, potential tools for the management of soil bacterial communities.     

Chrysonila sitophila (TFB-27441): A hyperlignolytic strain

Summary C. sitophila strain TFB-27441 showed 2–3 times higher lignolytic activity thanPhanerochaete chrysosporium (BKM-F-1767 strain). Lignin had a marked effect on the ligninase activity indicating that some induction or activation mechanism is involved in lignin degradation byC. sitophila.     

Site-specific gap-misrepair mutagenesis by O4-ethylthymine

The mutagenicity of the DNA base O-alkylation adduct, O4-ethylthymine, specifically incorporated into the plasmid vector pUC8 at the unique SalI and HincII recognition sites, was studied in vivo. Escherichia coli, Micrococcus luteus and AMV DNA polymerases catalyze the incorporation of O4-ethylTMP against template adenine and guanine residues, resulting in DNA sequence alteration during subsequent replication in the host E. coli K-12 strain JM83. The greatest mutation frequency was observed with error-prone AMV DNA polymerase. High levels of cognate restriction endonuclease-resistant mutant plasmid isolates were obtained by gap replication repair in the presence of O4-ethylTTP. The yields of mutant isolates were dependent upon the relative concentration of the competing pyrimidine deoxynucleoside triphosphates, TTP and dCTP, in the misreplication reaction. Repair of incorporated O4-ethylTMP of plasmid DNA by in vitro treatment with specific alkyltransferase, prior to transformation in the host, effectively increases the mutagenic efficiency of the adduct. The results obtained are consistent with the high miscoding potential O4-ethylthymine observed in in vitro studies and its ability to base-pair with noncomplementary guanine residues in DNA.     

Use of Microdialysis for Monitoring Tyrosine Hydroxylase Activity in the Brain of Conscious Rats

An on-line microdialysis system was developed which monitored the 3,4-dihydroxyphenylalanine (DOPA) formation in the striatum during infusion of a submicromolar concentration of an L-aromatic amino-acid decarboxylase inhibitor (NSD 1015). The absence of DOPA in dialysates of 6-hydroxydopamine-pretreated rats and the disappearance of DOPA after administration of alpha-methyl-p-tyrosine indicated that the dialyzed DOPA was derived from dopaminergic nerve terminals. Next we investigated whether the steady-state DOPA concentration in striatal dialysates could be considered as an index of tyrosine hydroxylase activity. The increase in DOPA output after intraperitoneal administration of haloperidol or gamma-butyrolactone and the decrease in DOPA output after intraperitoneal administration of apomorphine are in excellent agreement with results of postmortem studies, in which a decarboxylase inhibitor was used to measure the activity of tyrosine hydroxylase. The effect of haloperidol on DOPA formation was not visible when a U-shaped cannula (0.80 mm o.d.) was used. Some methodological problems related to microdialysis of the haloperidol-induced increase in DOPA formation are discussed. We concluded that the proposed model is a powerful and reliable in vivo method to monitor tyrosine hydroxylase activity in the brain. The method is of special interest for investigating the effect of compounds which are not able to pass the blood-brain barrier. As an application of the method in the latter situation, we report the effect of infusion the neurotoxin 1-methyl-4-phenylpyridinium ion (10 mmol/L infused over 20 min) on the activity of striatal tyrosine hydroxylase.     

Phylogeny of Greya (Lepidoptera: Prodoxidae), based on nucleotide sequence variation in mitochondrial cytochrome oxidase I and II: congruence with morphological data

The phylogeny of Greya Busck (Lepidoptera: Prodoxidae) was inferred from nucleotide sequence variation across a 765-bp region in the cytochrome oxidase I and II genes of the mitochondrial genome. Most parsimonious relationships of 25 haplotypes from 16 Greya species and two outgroup genera (Tetragma and Prodoxus) showed substantial congruence with the species relationships indicated by morphological variation. Differences between mitochondrial and morphological trees were found primarily in the positions of two species, G. variabilis and G. pectinifera, and in the branching order of the three major species groups in the genus. Conflicts between the data sets were examined by comparing levels of homoplasy in characters supporting alternative hypotheses. The phylogeny of Greya species suggests that host-plant association at the family level and larval feeding mode are conservative characters. Transition/transversion ratios estimated by reconstruction of nucleotide substitutions on the phylogeny had a range of 2.0-9.3, when different subsets of the phylogeny were used. The decline of this ratio with the increase in maximum sequence divergence among taxa indicates that transitions are masked by transversions along deeper internodes or long branches of the phylogeny. Among transitions, substitutions of A-->G and T-->C outnumbered their reciprocal substitutions by 2-6 times, presumably because of the approximately 4:1 (77%) A+T-bias in nucleotide base composition. Of all transversions, 73%-80% were A<-->T substitutions, 85% of which occurred at third positions of codons; these estimates did not decrease with an increase in maximum sequence divergence of taxa included in the analysis. The high frequency of A<-->T substitutions is either a reflection or an explanation of the 92% A+T bias at third codon positions.      

Comparison of European and US biological indicators for ethylene oxide sterilization

Summary Biological indicators (BIs) are used to monitor ethylene oxide (EO) gas sterilization processes for medical devices. Several European and United States BIs for EO sterilization were evaluated for resistance according to both United States Pharmacopeia (USP) XXI and United Kingdom's (UK) tests for D-values. US BIs areB. subtilis var. niger spores on paper strips or disc carriers while European BIs use aluminum strips, quartz sand, or cotton yarn. Numerous BIs per run and runs per lot, as well as 2–3 different lots of BIs from each manufacturer, were examined. Both British and US BIs met their respective label claims for rates of inactivation when tested against British and USP EO test parameters, respectively. However, Danish BIs, on cotton yarn or quartz sand, were not inactivated following USP specifications during the exposure dwell times tested (600 mg L^–1 EO, 54°C, 60% RH, 0–110 min). The Danish BIs will require further testing in order for us to determine if theirB. subtilis spores are unusually resistant to EO or if the spore carrier substrates protect the spores from the sterilizing gas. In conclusion, the British and American BIs for EO sterilization are equivalent in resistance despite differences in carrier substrate, recovery conditions, calculation methods for D-values, and the labeled sterilization conditions for use.     

Proposal for adoption of the base of the Undulograptus austrodentatus Biozone as a global Ordovician stage and series boundary level

The base of the Undulograptus austrodentatus Biozone appears to be a synchronous event that is widely recognizable within graptolitic facies around the world. It occurs within an interval in which graptolite species ranges are now well known and in which there is a rapid turnover in the composition of graptolite faunas. This turnover reflects the rapid evolutionary radiation of the Diplograptacea simultaneously with the appearance of several distinctive pseudisograptid and glossograptid species. These events provide the basis for the recognition of two thin but widely applicable subzones; a lower Arienigraptus zhejiangensis Subzone and an upper U. sinicus Subzone. The occurrence of the lower boundary of the U. austrodentatus Biozone within a succession of first appearances also permits accurate and reliable identification of the boundary as well as assessment of stratigraphic completeness across the boundary interval in correlated sections. Diverse graptolite faunas of late Yapeenian and early Darriwilian age occur in association with the Histiodella altifrons Biozone of the North American midcontinent conodont zonation and the Paroistodus originalis and Microzarkodina parva biozones of the North Atlantic conodont zonation. They also occur in association with the shelly-fossil zonations developed for several different continents. These features of the base of the U. austrodentatus Biozone make it a suitable level for use as the boundary level for a global stage. Its stratigraphic position within the Ordovician System relative to other likely global stages as well as its coincidence with one of the major events in graptolite evolutionary history suggest that this level also may be a suitable level for the base of a global Middle Ordovician Series.Ordovician System, Ordovician stages, graptolite zonation, chronostratigraphy, international correlation. Charles E. Mitchell and Jörg Maletz, Department of Geology, State University of New York at Buffalo, Buffalo, New York 14260-1550, USA; 13th July, 1994; revised 22nd May, 1995.     

Heterogeneity of Intermediate Filament Expression in Vascular Smooth Muscle: A Gradient in Desmin Positive Cells from the Rat Aortic Arch to the Level of the Arteria Iliaca Communis

The display of the two distinct intermediate filament proteins, desmin and vimentin, in rat vascular smooth muscle tissue was studied by immunofluorescence microscopy on frozen sections of aorta and other blood vessels. Vascular smooth muscle cells present in these vessels always appeared rich in vimentin. However, staining of sections covering six distinct but contiguous parts of the aorta showed that the number of desmin containing cells was low distal to the truncus brachiocephalicus, but increases until in distal parts of the aorta and in the arteria iliaca communis almost all cells appear positive for desmin. Thus blood vessels show heterogeneity of intermediate filament expression not only in cross-section but can also display heterogeneity along their length. Muscular arteries such as the renal artery and the arteria femoralis, as well as arterioles and veins including the vena jugularis and the vena cava also contain desmin. Thus it may be that low numbers of desmin-positive cells are typical of elastic arteries, while muscular arteries and other blood vessels are characterized by large numbers of desmin-positive cells. We discuss whether desmin-positive and desmin-negative vascular smooth muscle cells may perform different functions and raise the possibility that desmin expression may coincide with the turn on of a specially regulated contractility program.