Natrinema salaciae sp. nov., a halophilic archaeon isolated from the deep, hypersaline anoxic Lake Medee in the Eastern Mediterranean Sea

Two halophilic archaea, strains MDB25(T) and MDB20, were isolated from a sample of the brine from Lake Medee, at a depth of 3050m, in the Mediterranean Sea. Cells of the organisms were Gram-negative, non-motile and pleomorphic, and colonies were red pigmented. Strains MDB25(T) and MDB20 showed optimum growth at 45°C, in 2.6-3.4M NaCl and at pH 7.0-8.0. The major polar lipids of the two strains were phosphatidylglycerol (PG1 and PG2), phosphatidylglycerol phosphate methyl ester (PGP-Me) and mannose-2,6-dissulfate (1→2)-glucose glycerol diether (S(2)-DGD). Menaquinone MK-8 and MK-8(H(2)) were the major respiratory quinones. The DNA G+C content of strain MDB25(T) was 63.0%. The strains were facultatively anaerobic but grew better under aerobic conditions, nitrate served as electron acceptor. Analysis of the almost complete 16S rRNA gene sequence indicated that the strains MDB25(T) and MDB20 represented a member of the genus Natrinema in the family Halobacteriaceae. Both strains formed a distinct cluster and were most closely related to Natrinema ejinorense JCM 13890(T) and Haloterrigena longa JCM 13562(T) (98.0% and 97.9% sequence similarity, respectively). Based on 16S rRNA gene sequence analysis, DNA-DNA hybridization results, physiological and biochemical characteristics we describe a new species represented by strain MDB25(T) (=DSM 25055(T) =JCM 17869(T)) for which we propose the name Natrinema salaciae sp. nov.     

Co-production of tannase and gallic acid by a novel Penicillium rolfsii (CCMB 714)

Abstract

A novel tannase and gallic acid-producing Penicillium rolfsii (CCMB 714) was isolated from cocoa leaves from the South of Bahia. The influence of nutritional sources and the simultaneous effect of parameters involved in the fermentation process were available. Tannase (9.97 U?mL^?1) and gallic acid (9?mg mL^?1) production were obtained in 48?h by submerged fermentation in non-optimized conditions. Among the carbon sources, tested gallic acid and tannic acid showed the highest tannase production (p<.05) when compared with methyl gallate and glucose. After optimization using the temperature and tannic acid concentration as variables with the Central Compound Rotational Design (CCRD), the maximal tannase production (25.6?U mL^?1) was obtained at 29.8?°C and 12.7%, respectively, which represents an increase of 2.56 times in relation to the initial activity. The parameters optimized for the maximum production of gallic acid (21.51?mg mL^?1) were 30?°C and 10% tannic acid. P. rolfsii CCMB 714 is a new strain with a high tannase and gallic acid production and the gallic acid produced is very important, mainly for its applications in the food and pharmaceutical industry.     

The levels of renin-angiotensin related components are modified in the hippocampus of rats submitted to pilocarpine model of epilepsy

We previously showed that patients with temporal lobe epilepsy (TLE) present an increased expression of angiotensin II (AngII) AT1 and AT2 receptors in the hippocampus, supporting the idea of an upregulation of renin-angiotensin system (RAS) in this disease. This study aimed to verify the relationship between the RAS and TLE during epileptogenesis. Levels of the peptides angiotensin I (AngI), angiotensin II (AngII) and angiotensin 1-7 (Ang 1-7), were detected by HPLC assay. Angiotensin AT1 and AT2 receptors, Mas mRNA receptors and angiotensin converting enzyme (ACE), tonin and neutral endopeptidase (NEP) mRNA were also quantified at the hippocampus of Wistar rats by real time PCR, during acute (n=10), silent (n=10) and chronic (n=10) phases of pilocarpine-induced epilepsy. We observed an increased peptide level of Ang1-7 into acute and silent phases, decreasing importantly (p≤0.05) in the chronic phase, suggesting that AngI may be converted into Ang 1-7 by NEP, which is present in high levels in these periods. Our results also showed increased peptide level of AngII in the chronic phase of this model. In contraposition, the ACE expression is reduced in all periods. These data suggest that angiotensinogen or AngI may be cleaved to AngII by tonin, which showed increased expression in all phases. We found changes in AT1, AT2 and Mas mRNA receptors levels suggesting that Ang1-7 could act at Mas receptor during the silent period. Herein, we demonstrated for the first time, changes in angiotensin-related peptides, their receptors as well as the releasing enzymes in the hippocampus of rats during pilocarpine-induced epilepsy.     

Linking canopy leaf area and light environments with tree size distributions to explain Amazon forest demography

Forest biophysical structure – the arrangement and frequency of leaves and stems – emerges from growth, mortality and space filling dynamics, and may also influence those dynamics by structuring light environments. To investigate this interaction, we developed models that could use LiDAR remote sensing to link leaf area profiles with tree size distributions, comparing models which did not (metabolic scaling theory) and did allow light to influence this link. We found that a light environment‐to‐structure link was necessary to accurately simulate tree size distributions and canopy structure in two contrasting Amazon forests. Partitioning leaf area profiles into size‐class components, we found that demographic rates were related to variation in light absorption, with mortality increasing relative to growth in higher light, consistent with a light environment feedback to size distributions. Combining LiDAR with models linking forest structure and demography offers a high‐throughput approach to advance theory and investigate climate‐relevant tropical forest change.     

Dengue,Zika, and Chikungunya viral circulation and hospitalization rates in Brazil from 2014 to 2019: An ecological study

BackgroundIn addition to their direct pathogenic effects, arthropod-borne (arboviruses) have been hypothesized to indirectly contribute to hospitalizations and death through decompensation of pre-existing comorbidities. Using nationwide data routinely collected from 1 January 2014 to 31 December 2019 in Brazil, we investigated whether local increases in arbovirus notifications were associated with excess hospitalization.MethodsWe estimated the relative risks for the association between municipality- and state-level increases in arboviral case notifications and age-standardized hospitalization rates (i.e., classified as direct or indirect based on ICD-10 codes) using Bayesian multilevel models with random effects accounting for temporal and geographic correlations. For municipality-level analyses, we excluded municipalities with <200 notifications of a given arbovirus and further adjusted the models for the local Gini Index, Human Development Index, and Family Healthcare Strategy (Estratégia de Saúde da Família) coverage. Models for dengue, Zika, and chikungunya were performed separately.ResultsFrom 2014 to 2019, Brazil registered 7,566,330 confirmed dengue cases, 159,029 confirmed ZIKV cases, and 433,887 confirmed CHIKV cases. Dengue notifications have an endemic and seasonal pattern, with cases present in 5334 of the 5570 (95.8%) Brazilian municipalities and most (69.5%) registered between February and May. Chikungunya notifications followed a similar seasonal pattern to DENV but with a smaller incidence and were restricted to 4390 (78.8%) municipalities. ZIKV was only notified in 2581 (46.3%) municipalities. Increases in dengue and chikungunya notifications were associated with small increases in age-standardized arbovirus-related hospitalizations, but no consistent association was found with all-cause or other specific indirect causes of hospitalization. Zika was associated to increases in hospitalizations by neurological diseases.ConclusionsAlthough we found no clear association between increased incidence of the three arboviruses and excess risks of all-cause or indirect hospitalizations at the municipality- and state-levels, follow-up investigations at the individual-level are warranted to define any potential role of acute arbovirus infection in exacerbating risks of hospitalization from underlying conditions.     

Structural studies and biological evaluation of T30695 variants modified with single chiral glycerol-T reveal the importance of LEDGF/p75 for the aptamer anti-HIV-integrase activities

Some G-quadruplex (GQ) forming aptamers, such as T30695, exhibit particularly promising properties among the potential anti-HIV drugs. T30695?G-quadruplex binds to HIV-1 integrase (IN) and inhibits its activity during 3′-end processing at nanomolar concentrations. Herein we report a study concerning six T30695-GQ variants, in which the R or S chiral glycerol T, singly replaced the thymine residues at the T30695?G-quadruplex loops. CD melting, EMSA and HMRS experiments provided information about the thermal stability and the stoichiometry of T30695-GQ variants, whereas CD and ¹H NMR studies were performed to evaluate the effects of the modifications on T30695-GQ topology. Furthermore, LEDGF/p75 dependent and independent integration assays were carried out to evaluate how T loop modifications impact T30695-GQ biological activities. The obtained results showed that LEDGF/p75 adversely affects the potencies of T30695 and its variants. The IN inhibitory activities of the modified aptamers also depended on the position and on the chirality (R or S) of glycerol T loop in the GQ, mostly regardless of the G-quadruplex stabilities. In view of our and literature data, we suggest that the allosteric modulation of IN tetramer conformations by LEDGF/p75 alters the interactions between the aptamers and the enzyme. Therefore, the new T30695 variants could be suitable tools in studies aimed to clarify the HIV-1 IN tetramers allostery and its role in the integration activity.     

The mitochondrial calcium uniporter is a multimer that can include a dominant‐negative pore‐forming subunit

Mitochondrial calcium uniporter (MCU) channel is responsible for Ruthenium Red‐sensitive mitochondrial calcium uptake. Here, we demonstrate MCU oligomerization by immunoprecipitation and Förster resonance energy transfer (FRET) and characterize a novel protein (MCUb) with two predicted transmembrane domains, 50% sequence similarity and a different expression profile from MCU. Based on computational modelling, MCUb includes critical amino‐acid substitutions in the pore region and indeed MCUb does not form a calcium‐permeable channel in planar lipid bilayers. In HeLa cells, MCUb is inserted into the oligomer and exerts a dominant‐negative effect, reducing the [Ca²⁺]_mt increases evoked by agonist stimulation. Accordingly, in vitro co‐expression of MCUb with MCU drastically reduces the probability of observing channel activity in planar lipid bilayer experiments. These data unveil the structural complexity of MCU and demonstrate a novel regulatory mechanism, based on the inclusion of dominant‐negative subunits in a multimeric channel, that underlies the fine control of the physiologically and pathologically relevant process of mitochondrial calcium homeostasis.