Bare soil cover and arbuscular mycorrhizal community in the first montane forest restoration in Central Argentina

Soil erosion affects extensive areas worldwide and must be urgently reduced promoting plant cover and beneficial microorganisms associated with plants, including arbuscular mycorrhizal fungi (AMF). In mountain environments, plant cover is difficult to enhance due to harsh conditions during the dry season and steep slopes. Our objective was to evaluate the percentage of the soil surface covered by plants and the AMF community associated with trees 12.5 years after planting during forest restoration efforts in microsites at different levels of soil degradation. The study was performed in the first montane forest restoration initiative of Central Argentina, where one of the trials consisted of planting Polylepis australis saplings at microsites with different levels of soil degradation: high, intermediate, and low. After 12.5 years, percentage of bare soil cover was significantly reduced by 36 and 37% in the high and intermediate degradation microsites, respectively. Low degradation microsites were initially very low in bare soil and did not significantly change. Mycorrhizal colonization, hyphae, vesicles, arbuscules, AMF diversity, and community structure were similar among microsite types. Percentage of hyphal entry points was higher at microsites with low degradation, number of spores was higher in high and intermediate degradation, and species richness was higher in high degradation. Acaulospora and Glomus were the most abundant genera in all microsites. We conclude that even in the most degraded microsites around 2.8% of the bare soil is covered by vegetation each year and that the arbuscular mycorrhizal community is highly tolerant and adapted to soils with different disturbance types.     

Ectomycorrhizae between <Emphasis Type="Italic">Alnus acuminata</Emphasis> H.B.K. and <Emphasis Type="Italic">Naucoria escharoides</Emphasis> (Fr.:Fr.) Kummer from Argentina

Field ectomycorrhizae of Naucoria escharoides on Alnus acuminata ("andean alder", "aliso del cerro") are described in detail for the first time. Naturally occurring ectomycorrhizal roots were sampled beneath sporocarps of N. escharoides. The samples were taken from four natural forest plots at two homogeneous A. acuminata sites (Tucumán and Catamarca Provinces, Argentina). The ectomycorrhizae were characterized morphologically and compared by means of PCR/RFLP analysis of the internal transcribed spacer region of the nuclear rDNA. The most important morphological features of the ectomycorrhizae are a white to pale yellow mantle, simple to monopodial branches, hyaline emanating hyphae, abundant hyphal bundles emerging more or less perpendicularly from a plectenchymatous mantle, and an acute or rounded apex with or without a mantle. N. escharoides fruitbodies have white basal mycelium with emanating hyphae similar to those of andean alder ectomycorrhizae. The RFLP profiles of sporocarps and mycorrhizae were the same.     

Aerobic secondary utilization of a non-growth and inhibitory substrate 2,4,6-trichlorophenol by Sphingopyxis chilensis S37 and sphingopyxis-like strain S32

This paper reports 2,4,6-trichlorophenol (246TCP) degradation bySphingopyxis chilensis S37 and Sphingopyxis chilensis-like strain S32,which were unable to use 246TCP as the sole carbon and energy source. In R2A broth, the strainsdegraded 246TCP up to 0.5 mM. Results with mixtures of different 246TCP and glucose concentrations in mineral salt media demonstrated dependence on glucose to allow bacterial growth and degradation of 246TCP. Strain S32 degraded halophenol up to 0.2 mM when 5.33 mM glucose was simultaneously added, while strain S37 degraded the compound up to 0.1 mM when 1.33 mM glucose was added. These 246TCP concentrations were lethal for inocula in absence of glucose. Stoichiometricreleases of chloride and analysis by HPLC, GC-ECD and GC-MS indicated 246TCP mineralisation by both strains. To our knowledge, this is the first report of bacteriaable to mineralize a chlorophenol as a non-growth and inhibitory substrate. The concept of secondary utilization instead of cometabolism is proposed for this activity.     

Functional expression of H4 histamine receptor in human natural killer cells, monocytes, and dendritic cells

We describe here the protein expression of H4 histamine receptor in cells of the innate immune system, which include NK cells, monocytes, and dendritic cells (DCs). Anti-H4R specifically stained permeabilized NK cells, THP-1 clone 15 monocytes, and DCs. This binding was inhibited by incubating anti-H4R Ab with its corresponding peptide. Histamine induced NK cells, THP-1 clone 15 cells, and DCs chemotaxis with high affinity. The ED(50) chemotactic effect was 5 nM, 6.8 nM, and 2.7 nM for NK cells, THP-1 clone 15 cells, and DCs, respectively. Thioperamide, an H3R/H4R antagonist, inhibited histamine-induced chemotaxis in all these cells. However, histamine failed to induce the mobilization of [Ca(2+)](i) in NK cells and THP-1 clone 15 cells, but it induced calcium fluxes in DCs. Using a new method of detecting NK cell-mediated cytolysis, it was observed that NK cells efficiently lysed K562 target cells and that histamine did not affect this NK cell activity. In summary, this is the first demonstration of the protein expression of H4 receptor in NK cells. Also, the results of the chemotactic effects of histamine on NK cells and THP-1 cells are novel. These results may shed some light on the colocalization of cells of innate immune arm at sites of inflammation. They are also important for developing drugs that target H4R for the treatment of various disorders, such as autoimmune and immunodeficient diseases.     

Loss of DNA: a plausible molecular level explanation for crustacean neuropeptide gene evolution

Alignment of nucleotides of APGWamide, RPCH and AKH genes gives region stretches (common regions) present in all family member variants. Common regions were separated by gap sections in the larger variants of family members. Consensus sequences for single polynucleotides from virtual hybrid molecules of DNA were obtained by joining the common regions of DNA and deleting the extra DNA nucleotides. Conceptual translation of these virtual hybrids resulted in polypeptides similar to APGWamide, RPCH and the AKH pre-pro-peptide. Virtual polypeptides were also similar to LWamide and RFamide along hydras to mammals. DNA loss probably explains the origin of neuropeptides.     

Comparison of Macromolecular Oxidation by Reactive Oxygen Species in Three Bacterial Genera Exposed to Different Antibiotics

Proteins and lipids maybe important targets of oxidation and this may alter their functions. We evaluated whether ceftazidima (CAZ), piperacillin (PIP), chloramphenicol (CMP), and ciprofloxacin (CIP) could oxidize the macromolecules in the three bacterial genera Staphylococcus aureus, Escherichia coli, and Pseudomonas aeruginosa. There was an increase in lipid peroxidation observed in these three species. However, this was lower in the Gram negative bacteria than in S. aureus. A reduction of the carbonyl residue in S. aureus with ciprofloxacin was observed whereas in Gram negative bacteria the antibiotics increased the carbonyl residue with respect to the control. Although the strains suffered a rise in advanced oxidation protein products (AOPP) in the presence of ciprofloxacin, the S. aureus strain had a smaller increase of AOPP than the other strains. The results described in this article provide data about the susceptibility of the three bacterial genera to the oxidative stress induced by the antibiotics studied.     

A simple and objective method for reproducible resting state network (RSN) detection in fMRI

Spatial Independent Component Analysis (ICA) decomposes the time by space functional MRI (fMRI) matrix into a set of 1-D basis time courses and their associated 3-D spatial maps that are optimized for mutual independence. When applied to resting state fMRI (rsfMRI), ICA produces several spatial independent components (ICs) that seem to have biological relevance - the so-called resting state networks (RSNs). The ICA problem is well posed when the true data generating process follows a linear mixture of ICs model in terms of the identifiability of the mixing matrix. However, the contrast function used for promoting mutual independence in ICA is dependent on the finite amount of observed data and is potentially non-convex with multiple local minima. Hence, each run of ICA could produce potentially different IC estimates even for the same data. One technique to deal with this run-to-run variability of ICA was proposed by [1] in their algorithm RAICAR which allows for the selection of only those ICs that have a high run-to-run reproducibility. We propose an enhancement to the original RAICAR algorithm that enables us to assign reproducibility p-values to each IC and allows for an objective assessment of both within subject and across subjects reproducibility. We call the resulting algorithm RAICAR-N (N stands for null hypothesis test), and we have applied it to publicly available human rsfMRI data (http://www.nitrc.org). Our reproducibility analyses indicated that many of the published RSNs in rsfMRI literature are highly reproducible. However, we found several other RSNs that are highly reproducible but not frequently listed in the literature.     

Thymol derivatives from Eupatorium glechonophyllum

The known 10-acetoxy-8,9-epoxythymolisobutyrate and the new 8,9-dihydroxy-10-acetoxythymolisobutyrate and 8,9,10-trihydroxythymol have been isolated from the thallus of Eupatorium glechonophyllum. The acetonide of the last compound was also obtained. The possibility that the new compounds are artefacts is discussed.     

Interactions between natural killer cells and antibody Fc result in enhanced antibody neutralization of human immunodeficiency virus type 1

Antibodies can prevent lentivirus infections in animals and may play a role in controlling viral burden in established infection. In preventing and particularly in controlling infection, antibodies likely function in the presence of large quantities of virus. In this study, we explored the mechanisms by which antibodies neutralize large inocula of human immunodeficiency virus type 1 (HIV-1) on different target cells. Immunoglobulin G (IgG) from HIV-infected patients was tested for neutralizing activity against primary R5 strains of HIV-1 at inocula ranging from 100 to 20,000 50% tissue culture infective doses. At all virus inocula, inhibition by antibody was enhanced when target cells for virus growth were monocyte-depleted, peripheral blood mononuclear cells (PBMCs) rather than CD4(+) lymphocytes. However, enhanced inhibition on PBMCs was greatest with larger amounts of virus. Depleting PBMCs of natural killer (NK) cells, which express Fc receptors for IgG (FcgammaRs), abrogated the enhanced antibody inhibition, whereas adding NK cells to CD4(+) lymphocytes restored inhibition. There was no enhanced inhibition on PBMCs when F(ab')(2) was used. Further experiments demonstrated that the release of beta-chemokines, most likely through FcgammaR triggering of NK cells, contributed modestly to the antiviral activity of antibody on PBMCs and that antibody-coated virus adsorbed to uninfected cells provided a target for NK cell-mediated inhibition of HIV-1. These results indicate that Fc-FcgammaR interactions enhance the ability of antibody to neutralize HIV-1. Since FcgammaR-bearing cells are always present in vivo, FcgammaR-mediated antibody function may play a role in the ability of antibody to control lentivirus infection.