The composition of arbuscular mycorrhizal fungal communities differs among the roots,spores and extraradical mycelia associated with five Mediterranean plant species

Arbuscular mycorrhizal fungi (AMF) are essential constituents of most terrestrial ecosystems. AMF species differ in terms of propagation strategies and the major propagules they form. This study compared the AMF community composition of different propagule fractions – colonized roots, spores and extraradical mycelium (ERM) – associated with five Mediterranean plant species in Sierra de Baza Natural Park (Granada, Spain). AMF were identified using 454 pyrosequencing of the SSU rRNA gene. A total of 96 AMF phylogroups [virtual taxa (VT)] were detected in the study site, including 31 novel VT. After per‐sample sequencing depth standardization, 71 VT were recorded from plant roots, and 47 from each of the spore and ERM fractions. AMF communities differed significantly among the propagule fractions, and the root‐colonizing fraction differed among host plant species. Indicator VT were detected for the root (13 Glomus VT), spore (Paraglomus VT281, VT336, Pacispora VT284) and ERM (Diversispora VT62) fractions. This study provides detailed evidence from a natural system that AMF taxa are differentially allocated among soil mycelium, soil spores and colonized root propagules. This has important implications for interpreting AMF diversity surveys and designing applications of AMF in vegetation restoration.     

Olanzapine-induced hyperphagia and weight gain associate with orexigenic hypothalamic neuropeptide signaling without concomitant AMPK phosphorylation

The success of antipsychotic drug treatment in patients with schizophrenia is limited by the propensity of these drugs to induce hyperphagia, weight gain and other metabolic disturbances, particularly evident for olanzapine and clozapine. However, the molecular mechanisms involved in antipsychotic-induced hyperphagia remain unclear. Here, we investigate the effect of olanzapine administration on the regulation of hypothalamic mechanisms controlling food intake, namely neuropeptide expression and AMP-activated protein kinase (AMPK) phosphorylation in rats. Our results show that subchronic exposure to olanzapine upregulates neuropeptide Y (NPY) and agouti related protein (AgRP) and downregulates proopiomelanocortin (POMC) in the arcuate nucleus of the hypothalamus (ARC). This effect was evident both in rats fed ad libitum and in pair-fed rats. Of note, despite weight gain and increased expression of orexigenic neuropeptides, subchronic administration of olanzapine decreased AMPK phosphorylation levels. This reduction in AMPK was not observed after acute administration of either olanzapine or clozapine. Overall, our data suggest that olanzapine-induced hyperphagia is mediated through appropriate changes in hypothalamic neuropeptides, and that this effect does not require concomitant AMPK activation. Our data shed new light on the hypothalamic mechanism underlying antipsychotic-induced hyperphagia and weight gain, and provide the basis for alternative targets to control energy balance.     

Torque teno sus virus (TTSuV) in cell cultures and trypsin

Torque teno sus virus (TTSuV), a member of the family Anelloviridae, is a single-stranded, circular DNA virus, widely distributed in swine populations. Presently, two TTSuV genogroups are recognized: Torque teno sus virus 1 (TTSuV1) and Torque teno sus virus 2 (TTSuV2). TTSuV genomes have been found in commercial vaccines for swine, enzyme preparations and other drugs containing components of porcine origin. However, no studies have been made looking for TTSuV in cell cultures. In the present study, a search for TTSuV genomes was carried out in cell culture lineages, in sera used as supplement for cell culture media as well as in trypsin used for cell disaggregation. DNA obtained from twenty-five cell lineages (ten from cultures in routine multiplication and fifteen from frozen ampoules), nine samples of sera used in cell culture media and five batches of trypsin were examined for the presence of TTSuV DNA. Fifteen cell lineages, originated from thirteen different species contained amplifiable TTSuV genomes, including an ampoule with a cell lineage frozen in 1985. Three cell lineages of swine origin were co-infected with both TTSuV1 and TTSuV2. One batch of trypsin contained two distinct TTSuV1 plus one TTSuV2 genome, suggesting that this might have been the source of contamination, as supported by phylogenetic analyses of sequenced amplicons. Samples of fetal bovine and calf sera used in cell culture media did not contain amplifiable TTSuV DNA. This is the first report on the presence of TTSuV as contaminants in cell lineages. In addition, detection of the viral genome in an ampoule frozen in 1985 provides evidence that TTSuV contamination is not a recent event. These findings highlight the risks of TTSuV contamination in cell cultures, what may be source for contamination of biological products or compromise results of studies involving in vitro multiplied cells.     

Structure of the human gastric bacterial community in relation to Helicobacter pylori status

The human stomach is naturally colonized by Helicobacter pylori, which, when present, dominates the gastric bacterial community. In this study, we aimed to characterize the structure of the bacterial community in the stomach of patients of differing H. pylori status. We used a high-density 16S rRNA gene microarray (PhyloChip, Affymetrix, Inc.) to hybridize 16S rRNA gene amplicons from gastric biopsy DNA of 10 rural Amerindian patients from Amazonas, Venezuela, and of two immigrants to the United States (from South Asia and Africa, respectively). H. pylori status was determined by PCR amplification of H. pylori glmM from gastric biopsy samples. Of the 12 patients, 8 (6 of the 10 Amerindians and the 2 non-Amerindians) were H. pylori glmM positive. Regardless of H. pylori status, the PhyloChip detected Helicobacteriaceae DNA in all patients, although with lower relative abundance in patients who were glmM negative. The G2-chip taxonomy analysis of PhyloChip data indicated the presence of 44 bacterial phyla (of which 16 are unclassified by the Taxonomic Outline of the Bacteria and Archaea taxonomy) in a highly uneven community dominated by only four phyla: Proteobacteria, Firmicutes, Actinobacteria and Bacteroidetes. Positive H. pylori status was associated with increased relative abundance of non-Helicobacter bacteria from the Proteobacteria, Spirochetes and Acidobacteria, and with decreased abundance of Actinobacteria, Bacteroidetes and Firmicutes. The PhyloChip detected richness of low abundance phyla, and showed marked differences in the structure of the gastric bacterial community according to H. pylori status.     

Microplate-based high throughput screening procedure for the isolation of lipid-rich marine microalgae

Background

Termites are highly effective at degrading lignocelluloses, and thus can be used as a model for studying plant cell-wall degradation in biological systems. However, the process of lignin deconstruction and/or degradation in termites is still not well understood.

Methods

We investigated the associated structural modification caused by termites in the lignin biomolecular assembly in softwood tissues crucial for cell-wall degradation. We conducted comparative studies on the termite-digested (i.e. termite feces) and native (control) softwood tissues with the aid of advanced analytical techniques: ¹³C crosspolarization magic angle spinning and nuclear magnetic resonance (CP-MAS-NMR) spectroscopy, flash pyrolysis with gas chromatography mass spectrometry (Py-GC/MS), and Py-GC-MS in the presence of tetramethylammonium hydroxide (Py-TMAH)-GC/MS.

Results

The ¹³C CP/MAS NMR spectroscopic analysis revealed an increased level of guaiacyl-derived (G unit) polymeric framework in the termite-digested softwood (feces), while providing specific evidence of cellulose degradation. The Py-GC/MS data were in agreement with the ¹³C CP/MAS NMR spectroscopic studies, thus indicating dehydroxylation and modification of selective intermonomer side-chain linkages in the lignin in the termite feces. Moreover, Py-TMAH-GC/MS analysis showed significant differences in the product distribution between control and termite feces. This strongly suggests that the structural modification in lignin could be associated with the formation of additional condensed interunit linkages.

Conclusion

Collectively, these data further establish: 1) that the major β-O-4' (β-aryl ether) was conserved, albeit with substructure degeneracy, and 2) that the nature of the resulting polymer in termite feces retained most of its original aromatic moieties (G unit-derived). Overall, these results provide insight into lignin-unlocking mechanisms for understanding plant cell-wall deconstruction, which could be useful in development of new enzymatic pretreatment processes mimicking the termite system for biochemical conversion of lignocellulosic biomass to fuels and chemicals.     

Acute porphyrias in the Argentinean population: a review.

The porphyrias are a group of inherited metabolic disorders of heme biosynthesis which result from a partial deficiency in one of its seven specific enzymes, after its first and rate limiting enzyme, delta-aminolevulinic acid synthetase. They can be classified on the basis of their clinical manifestations into cutaneous, acute and mixed disorders. Acute intermittent porphyria (AIP) is the most common type of hepatic acute porphyrias, inherited as an autosomal dominant trait, caused by a defect in the gene which codifies for the heme enzyme porphobilinogen deaminase. Its prevalence in the Argentinean population is about 1:125,000. A partial deficiency in another enzyme, protoporphyrinogen oxidase, produces variegate porphyria (VP), the second acute porphyria most frequent in the Argentinean population (1:600,000). Here, we review all the mutations we have found in 46 AIP and 9 VP unrelated Argentinean patients. To screen for mutations in symptomatic patients, we have proposed a geneticresearch strategy.