The genomic sequence of the accidental pathogen Legionella pneumophila

We present the genomic sequence of Legionella pneumophila, the bacterial agent of Legionnaires' disease, a potentially fatal pneumonia acquired from aerosolized contaminated fresh water. The genome includes a 45-kilobase pair element that can exist in chromosomal and episomal forms, selective expansions of important gene families, genes for unexpected metabolic pathways, and previously unknown candidate virulence determinants. We highlight the genes that may account for Legionella's ability to survive in protozoa, mammalian macrophages, and inhospitable environmental niches and that may define new therapeutic targets.     

Long-term dynamics of leaf and root decomposition and nitrogen release in a grey alder (Alnus incana (L.) Moench) and silver birch (Betula pendula Roth.) stands

The decomposition of the leaf litter, fine roots (d?<?2?mm) and coarser roots (2?≤?d?<?5?mm) of grey alder and silver birch, as well as of α-cellulose sheets using the litterbag method was studied in two experimental stands on Podzoluvisol soils in Southern Estonia. For both tree species, the coarser roots decomposed faster than the fine roots, (p?<?.05), tree species did not affect the decomposition rate of the roots (p?>?.5). The nitrogen (N) input to soil from aboveground litter was multiple times higher than the N flux from roots. The remaining relative ash-free mass of the leaves of grey alder and silver birch after three and a half years was similar. After 11 years the remaining relative ash-free mass of the fine and coarser roots of grey alder still accounted for around 10% of the initial value. For silver birch the remaining value was around 20% after 9 years. The litterbag method to underestimates in fertile soils the decomposition of organic matter and thus did not reflect the actual dynamics of decomposition.     

Information about the V Congress of the Dokuchaev Soil Science Society

Chronicle

Information about the V Congress of the Dokuchaev Soil Science Society     

Utilization of a rate enhancement hybridization buffer system for rapid in situ hybridization for the detection of porcine circovirus in cell culture and in tissues of pigs with postweaning multisystemic wasting syndrome.

A rapid in situ hybridization (ISH) technique for the detection of porcine circovirus (PCV) nucleic acid in cell culture and formalin-fixed paraffin-embedded tissues was developed. A fluorescein-labeled RNA probe was transcribed from a plasmid containing 530 bp of the ORF1 of a PCV isolated from a pig with postweaning multisystemic wasting syndrome (PMWS). Hybridization using standard hybridization buffer was performed at 42 C for 16 hours and was compared to hybridization using rate enhancement hybridization (REH) buffer at 67 C for 2 hours. Hybridization was detected with an alkaline phosphatase-conjugated antifluorescein antibody. In both cultured cells and tissues from pigs with PMWS, the signal intensity and number of labeled cells in sections hybridized with REH buffer were equal to those of sections hybridized with standard hybridization buffer. The total time required for ISH using the REH buffer is 7-8 hours, thus making this protocol suitable for application in routine PCV diagnosis.     

Experimental reproduction of severe disease in CD/CD pigs concurrently infected with type 2 porcine circovirus and porcine reproductive and respiratory syndrome virus

Three-week-old cesarean-derived colostrum-deprived (CD/CD) pigs were inoculated with porcine circovirus type 2 (PCV2, n = 19), porcine reproductive and respiratory syndrome virus (PRRSV, n = 13), concurrent PCV2 and PRRSV (PCV2/PRRSV, n = 17), or a sham inoculum (n = 12) to compare the independent and combined effects of these agents. Necropsies were performed at 7, 10, 14, 21, 35, and 49 days postinoculation (dpi) or when pigs became moribund. By 10 dpi, PCV2/PRRSV-inoculated pigs had severe dyspnea, lethargy, and occasional icterus; after 10 dpi, mortality in this group was 10/11 (91%), and all PCV2/ PRRSV-inoculated pigs were dead by 20 dpi. PCV2-inoculated pigs developed lethargy and sporadic icterus, and 8/19 (42%) developed exudative epidermitis; mortality was 5/19 (26%). PRRSV-inoculated pigs developed dyspnea and mild lethargy that resolved by 28 dpi. Microscopic lesions consistent with postweaning multisystemic wasting syndrome (PMWS) were present in both PCV2- and PCV2/PRRSV-inoculated pigs and included lymphoid depletion, necrotizing hepatitis, mild necrotizing bronchiolitis, and infiltrates of macrophages that occasionally contained basophilic intracytoplasmic inclusion bodies in lymphoid and other tissues. PCV2/ PRRSV-inoculated pigs also had severe proliferative interstitial pneumonia and more consistent hepatic lesions. The most severe lesions contained the greatest number of PCV2 antigen-containing cells. PRRSV-inoculated pigs had moderate proliferative interstitial pneumonia but did not develop bronchiolar or hepatic lesions or lymphoid depletion. All groups remained seronegative to porcine parvovirus. The results indicate that 1) PCV2 coinfection increases the severity of PRRSV-induced interstitial pneumonia in CD/CD pigs and 2) PCV2 but not PRRSV induces the lymphoid depletion, granulomatous inflammation, and necrotizing hepatitis characteristic of PMWS.     

Effect of isomorphic substitutions on the Mössbauer and magnetic parameters of goethite

The effect of the isomorphic substitutions in the goethite structure on its magnetic and Mössbauer parameters was studied. For this purpose, synthetic samples of Al-substituted goethite with particle sizes of 24–28 nm were obtained and studied by means of Mössbauer spectroscopy, X-ray diffractometry, electron microscopy, and magnetic measurements. It was found that an increase in the number of isomorphic ions in the structure of this iron hydroxide reduces its susceptibility, magnetization, and the effective magnetic field of the nucleus. In addition, the structural substitutions of aluminum for iron ions leads to a significant decrease in the temperature of the magnetic phase transition (the Neel temperature). The way to explain the experimental results on the basis of the Neel theory in the nearest-neighbor approximation was considered. The possibility to use the obtained results for studying the genesis of iron oxides and hydroxides in soils was shown by the example of East African laterites.     

Development of probes to differentiate porcine circovirus types 1 and 2 in vitro by in situ hybridization

Porcine circovirus type 1 (PCV1), a PK-15 cell line contaminant, and porcine circovirus type 2 (PCV2), associated with post-weaning multisystemic wasting syndrome (PMWS), are genetically and antigenically related. Several techniques have been developed to detect PCV, including in situ hybridization (ISH). Previously reported probes used for ISH may hybridize with both PCV1 and PCV2 nucleic acids. We attempted to produce probes for ISH that can detect and differentiate PCV2 from PCV1 in PCV-infected cells. Riboprobes were synthesized from the sense and antisense strands of both open reading frames 1 and 2 (ORF1 and ORF2) of PCV2. At 42 and 58 degrees C, the ORF1 antisense probe hybridized with nucleic acid from both PCV1- and PCV2-infected cells. At 58 degrees C, the ORF2 antisense probe hybridized with PCV2 nucleic acid but not with PCV1 nucleic acid. The ORF1 and ORF2 sense probes bound only with PCV2 nucleic acid. Both antisense strand probes produced stronger signals than the sense strand probes. The results showed that the PCV2 ORF1 antisense probe is the most likely probe to detect both PCV types while the ORF2 antisense probe is capable of discriminating between PCV1 and PCV2.     

Interaction-driven spectrum reconstruction in bilayer graphene

The nematic phase transition in electronic liquids, driven by Coulomb interactions, represents a new class of strongly correlated electronic ground states. We studied suspended samples of bilayer graphene, annealed so that it achieves very high quasiparticle mobilities (greater than 10(6) square centimers per volt-second). Bilayer graphene is a truly two-dimensional material with complex chiral electronic spectra, and the high quality of our samples allowed us to observe strong spectrum reconstructions and electron topological transitions that can be attributed to a nematic phase transition and a decrease in rotational symmetry. These results are especially surprising because no interaction effects have been observed so far in bilayer graphene in the absence of an applied magnetic field.     

Giant nonlocality near the Dirac point in graphene

Transport measurements have been a powerful tool for discovering electronic phenomena in graphene. We report nonlocal measurements performed in the Hall bar geometry with voltage probes far away from the classical path of charge flow. We observed a large nonlocal response near the Dirac point in fields as low as 0.1 tesla, which persisted up to room temperature. The nonlocality is consistent with the long-range flavor currents induced by the lifting of spin/valley degeneracy. The effect is expected to contribute strongly to all magnetotransport phenomena near the neutrality point.     

The Mycobiota of Eutrophic Peatlands

Eurasian Soil Science - The comprehensive study of mycobiota in full profiles of eutrophic peatlands based on abundance and diversity rates has been carried out in order to broaden the knowledge on...