Light sensing in chemotrophic bacteria has been relatively recently ascertained. In the human pathogen
, light modulates motility, biofilm formation, and virulence through the ...blue-light-sensing-using flavin (BLUF) photoreceptor BlsA. In addition, light can induce a reduction in susceptibility to certain antibiotics, such as minocycline and tigecycline, in a photoreceptor-independent manner. In this work, we identified new traits whose expression levels are modulated by light in this pathogen, which comprise not only important determinants related to pathogenicity and antibiotic resistance but also metabolic pathways, which represents a novel concept for chemotrophic bacteria. Indeed, the phenylacetic acid catabolic pathway and trehalose biosynthesis were modulated by light, responses that completely depend on BlsA. We further show that tolerance to some antibiotics and modulation of antioxidant enzyme levels are also influenced by light, likely contributing to bacterial persistence in adverse environments. Also, we present evidence indicating that surfactant production is modulated by light. Finally, the expression of whole pathways and gene clusters, such as genes involved in lipid metabolism and genes encoding components of the type VI secretion system, as well as efflux pumps related to antibiotic resistance, was differentially induced by light. Overall, our results indicate that light modulates global features of the
lifestyle.
The discovery that nonphototrophic bacteria respond to light constituted a novel concept in microbiology. In this context, we demonstrated that light could modulate aspects related to bacterial virulence, persistence, and resistance to antibiotics in the human pathogen
In this work, we present the novel finding that light directly regulates metabolism in this chemotrophic bacterium. Insights into the mechanism show the involvement of the photoreceptor BlsA. In addition, tolerance to antibiotics and catalase levels are also influenced by light, likely contributing to bacterial persistence in adverse environments, as is the expression of the type VI secretion system and efflux pumps. Overall, a profound influence of light on the lifestyle of
is suggested to occur.
Hepatic ammonia detoxification to urea is critical for the prevention of hyperammonemia and neurological damage. Hepatocyte mitochondrial aquaporin‐8 (AQP8) channels have been involved in ...ammonia‐derived ureagenesis. Herein, we studied whether the adenoviral gene transfer of human AQP8 (hAQP8) to hepatocyte mitochondria enhances ammonia conversion to urea. Using primary cultured rat hepatocytes, we first confirmed the mitochondrial expression of hAQP8 and then, using unlabeled or 15N‐labeled ammonia, we demonstrated that the urea synthesis was significantly enhanced in hAQP8‐transduced hepatocytes. Studies using isolated hAQP8‐expressing mitochondria also showed an increased ammonia metabolism. hAQP8 transduction was able to recover the impaired ammonia‐derived ureagenesis in hepatotoxin‐treated hepatocytes. Our data suggest that mitochondrially‐expressed hAQP8 enhances and improves hepatocyte ammonia conversion to urea, a finding with potential therapeutic implications for liver disease with impaired ammonia detoxification.
Capiglioni and coworkers show that the adenoviral gene transfer of human aquaporin‐8 to hepatocyte mitochondria enhances ammonia metabolism to urea and improves ammonia‐derived ureagenesis in hepatotoxin‐treated hepatocytes. The authors suggest that this finding has potential therapeutic implications for liver diseases with impaired ammonia detoxification.
BlsA is a BLUF photoreceptor present in Acinetobacter baumannii, responsible for modulation of motility, biofilm formation and virulence by light. In this work, we have combined physiological and ...biophysical evidences to begin to understand the basis of the differential photoregulation observed as a function of temperature. Indeed, we show that blsA expression is reduced at 37°C, which correlates with negligible photoreceptor levels in the cells, likely accounting for absence of photoregulation at this temperature. Another point of control occurs on the functionality of the BlsA photocycle itself at different temperatures, which occurs with an average quantum yield of photoactivation of the signaling state of 0.20 ± 0.03 at 15°C < T < 25°C, but is practically inoperative at T > 30°C, as a result of conformational changes produced in the nanocavity of FAD. This effect would be important when the photoreceptor is already present in the cell to avoid almost instantaneously further signaling process when it is no longer necessary, for example under circumstances of temperature changes possibly faced by the bacteria. This complex interplay between light and temperature would provide the bacteria clues of environmental location and dictate/modulate light photosensing in A. baumannii.
BL: blue‐light and D: dark. BlsA levels shown under BL or in D were represented schematically according to transcriptional and immunoblot data. It should be noted that BlsA levels are low in the cells. Stage A. BlsA performs photocycle under blue light at 24°C; photoregulation of motility occurs. Stages B & C. At 37°C, a fraction of BlsA aggregated (B) and probably degraded (C). Soluble fraction keeps FAD bound but is almost inactive to BL (B). No photoregulation of motility occurs. It should be noted that BlsA levels are low in the cells. Stage D. Back to 24°C, the soluble fraction is still photoactive. De novo synthesis of blsA could lead again to photoregulation (A).
Peach (
) is an important economically temperate fruit. The development follows double sigmoid curve with four phases (S1-S4). We centered our work in the early development. In addition to S1, we ...studied the very early stage (E) characterized by the lag zone of the exponential growing phase S1, and the second stage (S2) when the pit starts hardening. "Dixiland" peach fruit were collected at 9 (E), 29 (S1), and 53 (S2) days after flowering (DAF) and endocarp and mesocarp were separated. There was a pronounced decrease in total protein content along development in both tissues. Quantitative proteomic allowed the identification of changes in protein profiles across development and revealed the main biochemical pathways sustaining tissue differentiation. Protein metabolism was the category most represented among differentially proteins in all tissues and stages. The decrease in protein synthesis machinery observed during development would be responsible of the protein fall, rather than a proteolytic process; and reduced protein synthesis during early development would reroute cell resources to lignin biosynthesis. These changes were accompanied by net decrease in total amino acids in E1-S1 and increase in S1-S2 transitions. Amino acid profiling, showed Asn parallels this trend. Concerted changes in Asn and in enzymes involved in its metabolism reveal that increased synthesis and decreased catabolism of Asn may conduct to an Asn increase during very early development and that the β-Cyano-Alanine synthase/β-Cyano-Alanine hydratase could be the pathway for Asn synthesis in "Dixiland" peach fruit. Additionally, photosynthetic machinery decays during early development in mesocarp and endocarp. Proteins related to photosynthesis are found to a higher extent in mesocarp than in endocarp. We conclude mesocarpic photosynthesis is possible to occur early on the development, first providing both carbon and reductive power and latter only reductive power. Together with proteomic, histological tests and anatomical analysis help to provide information about changes and differences in cells and cell-walls in both tissues. Collectively, this work represents the first approach in building protein databases during peach fruit development focusing on endocarp and mesocarp tissues and provides novel insights into the biology of peach fruit development preceding pit hardening.
•Woolliness is accompanied by proteome reconfiguration in peach fruit.•Carbon oxidation processes take place in woolly peach fruit.•Drastic decrease of free amino acid levels are found in woolly ...peach fruit.•ROS staining is higher in woolly fruit when compared to healthy fruit.•The woolly phenotype can be triggered in highly similar biochemical contexts.
Fleshy fruit are susceptible to develop chilling injury (CI) disorders when stored at low temperatures for extended periods during the postharvest. In peach (Prunus persica L. Batsch) fruit, the woolly texture, expressed as a lack of juiciness, is the most important CI symptom. In the present work, we set up to study the metabolomic and proteomic differences of Spring Lady peach fruit, which, despite had been subjected to the same postharvest treatment (24 d at 0 °C followed by 5 d at 20 °C), display a contrasting woolliness phenotype. A drastic decrease in the content of sugars and sugar alcohols (sucrose, fructose, glucose, ribose, xylose, galactose, sorbitol and raffinose), as well as in all the amino acids detected (Ala, Asn, Gly, Glu, Ile, Ser, Thr, and Val), was found in woolly (WF) when compared to juicy fruit (JF). The quantitative proteomic analysis of JF and WF identified 227 differentially expressed proteins (DEP), from which 165 were increased and 62 decreased in WF with respect to JF. The identification of clusters of functionally associated proteins among the DEP revealed biochemical and physiological processes linked to the development of the woolly phenotype; such as sugar catabolism, amino acid usage, and proteome reconfiguration. On the other hand, a decrease of proteins involved in reactive oxygen species (ROS) detoxification, lower ascorbate peroxidase activity, and higher ROS levels, were found in the mesocarp of WF when compared to JF. Overall, this work identifies the induction of carbon oxidation processes, proteome reconfiguration, and increased ROS generation, as relevant metabolic signatures of woolliness development in peach fruit. Besides, the experimental approach used here clearly shows that the woolly phenotype can be triggered in similar biochemical contexts. The relevance of oxidative stress, probably as a consequence of an imbalance between ROS production and elimination, is highlighted as a causal mechanism of woolliness development in peach fruit.
Leaf peach curl is a devastating disease affecting leaves, flowers and fruits, caused by the dimorphic fungus Taphrina deformans. To gain insight into the mechanisms of fungus pathogenesis and plant ...responses, leaves of a resistant and two susceptible Prunus persica genotypes were inoculated with blastospores (yeast), and the infection was monitored during 120 h post inoculation (h.p.i.). Fungal dimorphism to the filamentous form and induction of reactive oxygen species (ROS), callose synthesis, cell death and defence compound production were observed independently of the genotype. Fungal load significantly decreased after 120 h.p.i. in the resistant genotype, while the pathogen tended to grow in the susceptible genotypes. Metabolic profiling revealed a biphasic re‐programming of plant tissue in susceptible genotypes, with an initial stage co‐incident with the yeast form of the fungus and a second when the hypha is developed. Transcriptional analysis of PRs and plant hormone‐related genes indicated that pathogenesis‐related (PR) proteins are involved in P. persica defence responses against T. deformans and that salicylic acid is induced in the resistant genotype. Conducted experiments allowed the elucidation of common and differential responses in susceptible versus resistant genotypes and thus allow us to construct a picture of early events during T. deformans infection.
Taphrina deformans is the causal leaf peach curl disease. For the first time, fungal dimorphism from the yeast to the filamentous phase was achieved in inoculated P. persica leaves. Induction of ROS, callose synthesis, cell death and defence compound production was observed in susceptible and resistant genotypes. Resistance against biotrophic T. deformans is associated with the activation of the salicylic‐acid‐dependent pathway, induction of phenolics and up‐regulation of defensin. A picture of early events during T. deformans infection is presented.
Severe droughts are predicted for the twenty-first century, which contrast with the increased demand for plant materials. Thus, to sustain future generations, a great challenge is to improve crop ...yield and water use efficiency (WUE), which is the carbon gained per water lost. Here, expression of maize NADP-malic enzyme (NADP-ME) in the guard and vascular companion cells of Nicotiana tabacum results in enhanced WUE, earlier flowering and shorter life cycle. Transgenic lines exhibit reduced stomatal aperture than wild-type (WT). Nevertheless, an increased net CO
fixation rate is observed, which results in less water consumption and more biomass production per water used. Transgenic lines export sugars to the phloem at higher rate than WT, which leads to higher sugars levels in phloem exudates and veins. Leaf quantitative proteomic profiling revealed drastic differences in proteins related to cell cycle, flowering, hormone signaling and carbon metabolism between transgenic lines and WT. We propose that the increased sugar export from leaves in the transgenic lines alleviates sugar negative feedback on photosynthesis and thus, stomatal closure takes place without a penalty in CO
assimilation rate. This results in improved WUE and accelerated overall life cycle, key traits for plant productivity in the near future world.
Aim
To evaluate the effects of neurodevelopmental treatment (NDT) in children with congenital Zika syndrome (CZS).
Methods
This prospective, interventional cohort study involved children with CZS ...undergoing follow‐up at a specialist centre in northeastern Brazil. The duration of the proposed NDT protocol was 1 year, with 45‐min sessions delivered one to five times weekly. Motor function, weight, height, head circumference and the incidence of comorbidities were evaluated in children before protocol initiation and then at 3, 6 and 12 months of treatment.
Results
Thirty children were evaluated (age mean 30.1 ± 3 months). Motor function improved from baseline to 6 months (P = 0.001). No difference in weight and head circumference z‐score (P = 0.51 and P = 0.29, respectively), but an increase in height z‐score (P < 0.001) was observed over the evaluation period. There was a reduction in the incidence of upper respiratory tract infections, pneumonia and urinary tract infections over the follow‐up period.
Conclusions
NDT proved to be a viable treatment approach that can improve motor function and reduce the incidence of comorbidities in children with CZS, while having no harmful effects on their growth.
Glycine-rich RNA-binding proteins (GRPs) are involved in the modulation of the post-transcriptional processing of transcripts and participate as an output signal of the circadian clock. However, ...neither GRPs nor the circadian rhythmic have been studied in detail in fleshy fruits as yet. In the present work, the GRP1 gene family was analysed in Micro-Tom tomato (Solanum lycopersicum L.) fruit. Three highly homologous LeGRP1 genes (LeGRP1a–c) were identified. For each gene, three products were found, corresponding to the unspliced precursor mRNA (pre-mRNA), the mature mRNA and the alternatively spliced mRNA (preLeGRP1a–c, mLeGRP1a–c and asLeGRP1a–c, respectively). Tomato GRPs (LeGRPs) show the classic RNA recognition motif and glycine-rich region, and were found in the nucleus and in the cytosol of tomato fruit. By using different Escherichia coli mutants, it was found that LeGRP1s contained in vivo RNA-melting abilities and were able to complement the cold-sensitive phenotype of BX04 cells. Particular circadian profiles of expression, dependent on the fruits’ developmental stage, were found for each LeGRP1 form. During ripening off the vine of fruits harvested at the mature green stage, the levels of all LeGRP1a–c forms drastically increased; however, incubation at 4°C prevented such increases. Analysis of the expression of all LeGRP1a–c forms suggests a positive regulation of expression in tomato fruit. Overall, the results obtained in this work reveal a complex pattern of expression of GRPs in tomato fruit, suggesting they might be involved in post-transcriptional modulation of circadian processes of this fleshy fruit.
Two maize plastidic NADP-malic enzyme isoforms have been characterized: the bundle sheath-located photosynthetic isoform (ZmC₄-NADP-ME) and a constitutively expressed one (Zm-nonC₄-NADP-ME). In this ...work, the characterization of the first maize cytosolic NADP-ME (ZmCytNADP-ME) is presented, which transcript is exclusively found in embryo and emerging roots. ZmCytNADP-ME expression in roots decreases with development, while Zm-nonC ₄ -NADP-ME increases concomitantly. On the other hand, ZmCytNADP-ME accumulation is differentially modulated by several stress conditions and shows coordination with that of Zm-nonC ₄ -NADP-ME in maize young roots. Recombinant ZmCytNADP-ME displays clearly distinct kinetic parameters and metabolic regulation than the plastidic isoforms. The particular properties and the specific-expression pattern of this novel isoform suggest that it may be involved in the control of cytosolic malate levels in emerging roots, e.g. during hypoxia. ZmCytNADP-ME is phylogenetically related to other cytosolic mono and dicot NADP-MEs, and data indicate that it belongs to an ancestral unique group among plant NADP-MEs.
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