Patatin-related phospholipase A: nomenclature, subfamilies and functions in plants

The release of fatty acids from membrane glycerolipids has been implicated in a variety of cellular processes, but the enzymes involved and their regulation are poorly understood in plants. One large group of acyl-hydrolyzing enzymes is structurally related to patatins. Patatins are potato tuber proteins with acyl-hydrolyzing activity, and the patatin catalytic domain is widely spread in bacterial, yeast, plant and animal enzymes. Recent results have indicated that patatin-related enzymes are involved in different cellular functions, including plant responses to auxin, elicitors or pathogens, and abiotic stresses and lipid mobilization during seed germination. In this review, we highlight recent developments regarding these enzymes and propose the nomenclature pPLA for the patatin-related phospholipase A enzyme.     

Prevalence and genetic characterisation of HTLV-1 and 2 dual infections in patients with pulmonary tuberculosis in Central-West Brazil

Human T-cell lymphotropic virus (HTLV) may impact the clinical course of tuberculosis (TB). Both infections are highly endemic in Brazil. The aim of this study was to assess the prevalence of HTLV-1/2 in TB patients in Central-West Brazil and to perform a genetic characterisation of the respective isolates. Of the 402 patients, six (1.49%) were positive for anti-HTLV and five (1.24%; 95% confidence interval: 0.46-3.05) were infected with HTLV-1/2. Genetic characterisation demonstrated that the four HTLV-1 isolates belonged to the Transcontinental subgroup A of the Cosmopolitan subtype a and that the HTLV-2 isolate belonged to subtype a (HTLV-2a/c). The prevalence of HTLV infection observed in this study is higher than that observed in local blood donors and the HTLV-1 and 2 subtypes identified are consistent with those circulating in Brazil.     

Regulatory phosphorylation of FXYD2 by PKC and cross interactions between FXYD2, plasmalemmal Ca-ATPase and Na,K-ATPase

FXYD2 is a regulatory peptide associated with the α-subunit of the kidney Na,K-ATPase. FXYD2 can be phosphorylated by PKA, and its phosphorylation activates Na,K-ATPase. Here we show that FXYD2 is phosphorylated by PKC (PKC-FXYD2-P), by PKA (PKA-FXYD2-P) or by PKA and PKC simultaneously (FXYD2-P₂) modulating both the erythrocyte Na,K-ATPase and the plasma membrane Ca²⁺-ATPase (PMCA). In erythrocyte ghosts, the addition of PKA-FXYD2-P activated Na,K-ATPase by 80%, while non-phosphorylated FXYD2 (np) activated only 55%. The addition of np FXYD2 did not affect PMCA basal activity, but FXYD2-P₂ increased the basal PMCA activity by up to 200%. Calmodulin-activated PMCA activity was increased by np FXYD2 (3-fold) or FXYD2-P₂ (2.5-fold). However, PKC-FXYD2-P increased PMCA activity only by 50%. In contrast, when PMCA was treated with PKA-FXYD2-P, the ATPase activity was inhibited by 50%. The effect of all forms of FXYD2-P on calcium uptake from PMCA resembled the pattern observed in ATP hydrolysis. Our results suggest that the FXYD2 anchoring site could be conserved among the P-ATPase family permitting cross regulation. The effects of FXYD2 on calcium uptake and calcium-stimulated ATP hydrolysis suggest a novel role for FXYD2 on PMCA.     

The reaction of azoles with 17-chloro-16-formylandrosta-5,16-dien-3β-yl-acetate: synthesis and structural elucidation of novel 16-azolylmethylene-17-oxoandrostanes

The synthesis and structural elucidation, by 1D and 2D NMR and X-ray diffraction techniques, of novel E/Z 16-azolylmethylene-17-oxoandrostanes 2-9 prepared from the Vilsmeier-Hack reaction product 17-chloro-16-formylandrosta-5,16-dien-3β-yl acetate 1 is reported. The reaction proceeds with pyrrole and pyrrole-alike nitrogen heterocycles such as 7-azaindole, indole, and 3-methylindole, in DMF, at 80 °C, in the presence of K₂CO₃, and allowed the attachment of privileged heterocyclic moieties, through the nitrogen atom to the steroid core at C16 via a methine carbon bridge, which is unprecedented in the literature and of potential synthetic and biological interest. Considerations on the possible reaction mechanism are included. All the synthesized compounds are new and are currently being tested for biological activities.     

The plant uncoupling protein homologues: a new family of energy-dissipating proteins in plant mitochondria.

Uncoupling proteins (UCPs) form a subfamily within the mitochondrial carrier protein family, which catalyze a free fatty acid-mediated proton recycling and can modulate the tightness of coupling between mitochondrial respiration and ATP synthesis. As in mammalian tissues, UCPs are rather ubiquitous in the plant kingdom and widespread in plant tissues in which they could have various physiological roles, such as heat production or protection against free oxygen radicals. The simultaneous occurrence in plant mitochondria of two putative energy-dissipating systems, namely UCP which dissipates the proton motive force, and alternative oxidase (AOX) which dissipates the redox potential, raises the question of their functional interactions.     

Analysing Twitter and web queries for flu trend prediction

Background

Social media platforms encourage people to share diverse aspects of their daily life. Among these, shared health related information might be used to infer health status and incidence rates for specific conditions or symptoms. In this work, we present an infodemiology study that evaluates the use of Twitter messages and search engine query logs to estimate and predict the incidence rate of influenza like illness in Portugal.

Results

Based on a manually classified dataset of 2704 tweets from Portugal, we selected a set of 650 textual features to train a Naïve Bayes classifier to identify tweets mentioning flu or flu-like illness or symptoms. We obtained a precision of 0.78 and an F-measure of 0.83, based on cross validation over the complete annotated set. Furthermore, we trained a multiple linear regression model to estimate the health-monitoring data from the Influenzanet project, using as predictors the relative frequencies obtained from the tweet classification results and from query logs, and achieved a correlation ratio of 0.89 (p < 0.001). These classification and regression models were also applied to estimate the flu incidence in the following flu season, achieving a correlation of 0.72.

Conclusions

Previous studies addressing the estimation of disease incidence based on user-generated content have mostly focused on the english language. Our results further validate those studies and show that by changing the initial steps of data preprocessing and feature extraction and selection, the proposed approaches can be adapted to other languages. Additionally, we investigated whether the predictive model created can be applied to data from the subsequent flu season. In this case, although the prediction result was good, an initial phase to adapt the regression model could be necessary to achieve more robust results.

     

Phylogenetic Analysis of Phenotypically Characterized Cryptococcus laurentii Isolates Reveals High Frequency of Cryptic Species

Background

Although Cryptococcus laurentii has been considered saprophytic and its taxonomy is still being described, several cases of human infections have already reported. This study aimed to evaluate molecular aspects of C. laurentii isolates from Brazil, Botswana, Canada, and the United States.

Methods

In this study, 100 phenotypically identified C. laurentii isolates were evaluated by sequencing the 18S nuclear ribosomal small subunit rRNA gene (18S-SSU), D1/D2 region of 28S nuclear ribosomal large subunit rRNA gene (28S-LSU), and the internal transcribed spacer (ITS) of the ribosomal region.

Results

BLAST searches using 550-bp, 650-bp, and 550-bp sequenced amplicons obtained from the 18S-SSU, 28S-LSU, and the ITS region led to the identification of 75 C. laurentii strains that shared 99–100% identity with C. laurentii CBS 139. A total of nine isolates shared 99% identity with both Bullera sp. VY-68 and C. laurentii RY1. One isolate shared 99% identity with Cryptococcus rajasthanensis CBS 10406, and eight isolates shared 100% identity with Cryptococcus sp. APSS 862 according to the 28S-LSU and ITS regions and designated as Cryptococcus aspenensis sp. nov. (CBS 13867). While 16 isolates shared 99% identity with Cryptococcus flavescens CBS 942 according to the 18S-SSU sequence, only six were confirmed using the 28S-LSU and ITS region sequences. The remaining 10 shared 99% identity with Cryptococcus terrestris CBS 10810, which was recently described in Brazil. Through concatenated sequence analyses, seven sequence types in C. laurentii, three in C. flavescens, one in C. terrestris, and one in the C. aspenensis sp. nov. were identified.

Conclusions

Sequencing permitted the characterization of 75% of the environmental C. laurentii isolates from different geographical areas and the identification of seven haplotypes of this species. Among sequenced regions, the increased variability of the ITS region in comparison to the 18S-SSU and 28S-LSU regions reinforces its applicability as a DNA barcode.     

Interaction of peptides with biomembranes assessed by potential-sensitive fluorescent probes.

Peptide-membrane interaction is an important step to be evaluated in a study of the activity and mode of action of several bioactive peptides. A variety of methods are available; however, few of them satisfy the criteria of being sensitive, biocompatible, versatile, easy to perform, and allowing real-time monitoring as the use of potential-sensitive fluorescent probes. Here we review methods for detecting the effects of membrane-active peptides, even those that are not intrinsically fluorescent, on the different types of membrane potentials, with a special emphasis on studies conducted with living cells. FPE is a probe sensitive to surface potential and detects electrostatic interactions at the water-lipid interface. Di-8-ANEPPS is sensitive to dipole potential and detects membrane incorporations. Transmembrane potential changes reveal major membrane destabilizations, such as in pore formation. The combination of the information obtained from the three potential variations can lead to a more elucidative picture of the mechanisms of the interaction of relevant peptides with biomembranes.