Evaluation of glial tumors: correlation between magnetic resonance imaging and histopathological analysis.

Objective: To determine the correlation of conventional and diffusion-weighted imaging findings on magnetic resonance imaging (MRI) of the brain, based on Visually AcceSAble Rembrandt Images (VASARI) criteria, with the histopathological grading of gliomas: low-grade or high-grade. Materials and Methods: Preoperative MRI scans of 178 patients with brain gliomas and pathological confirmation were rated by two neuroradiologists for tumor size, location, and tumor morphology, using a standardized imaging feature set based on the VASARI criteria. Results: In the univariate analysis, more than half of the MRI characteristics evaluated showed a significant association with the tumor grade. The characteristics most significantly associated with the tumor grade were hemorrhage; restricted diffusion; pial invasion; enhancement; and a non-contrast-enhancing tumor crossing the midline. In a multivariable regression model, the presence of enhancement and hemorrhage maintained a significant association with high tumor grade. The absence of contrast enhancement and restricted diffusion were associated with the presence of an isocitrate dehydrogenase gene mutation. Conclusion: Our data illustrate that VASARI MRI features, especially intratumoral hemorrhage, contrast enhancement, and multicentricity, correlate strongly with glial tumor grade.

Objetivo: Determinar a correlação dos achados de imagem convencional e de difusão na ressonância magnética (RM) do encéfalo, com base nos critérios Visually AcceSAble Rembrandt Images (VASARI), com a classificação histopatológica de gliomas: gliomas de baixo grau e gliomas de alto grau. Materiais e Métodos: Imagens de RM pré-cirúrgicas de 178 pacientes com gliomas cerebrais e confirmação patológica foram avaliadas por dois neurorradiologistas quanto ao tamanho, localização e morfologia do tumor usando um padrão de imagem baseado nos critérios VASARI. Resultados: Na análise univariada, mais da metade das características avaliadas apresentou associação significativa com o grau do tumor. Hemorragia, restrição à difusão, invasão pial, realce e tumor sem realce cruzando a linha média foram as características com associação mais significativa. No modelo de regressão multivariada, a presença de realce e hemorragia manteve associação significativa com tumores de alto grau. A ausência de realce pelo meio de contraste e a restrição da difusão foram associados à presença da mutação do gene isocitrato desidrogenase. Conclusão: Nossos dados ilustram que as características de RM do VASARI, especialmente hemorragia intratumoral, presença de realce de contraste e multicentricidade, forneceram uma correlação importante com o grau da neoplasia glial.

Predicting of novel homoserine dehydrogenase inhibitors against Paracoccidioides brasiliensis: integrating in silico and in vitro approaches.

Aim: To search for potential inhibitors to homoserine dehydrogenase (HSD) in Paracoccidioides brasiliensis the causative agent of paracoccidioidomycosis, an infection with a high mortality rate in Brazil.Materials & methods: The enzyme was modeled and used in the virtual screening of the compounds. The library was first screened by the Autodock, in which 66 molecules were better ranked than substrate, and then, also evaluated by the Molegro and Gold programs.Results: The HS23 and HS87 molecules were selected in common by the three programs, and ADME/Tox evaluation indicates they are not toxic. The molecular dynamics of PbHSD bonded to ligands showed stable complexes until 50 ns. To validate the results, compounds were purchased for assays of minimum inhibitory concentration (MIC), minimum fungicidal concentration (MFC), synergic profile with Amphotericin B (AmB) and cytotoxicity. The two molecules presented MIC of 32 µg/ml and MFC of 64 µg/ml against the P. brasiliensis (strain Pb18). They also showed synergistic activity with AmB and a lack of toxicity against Hela and Vero cell lines.Conclusion: These results suggest that the HS23 and HS87 are promising candidates as PbHSD inhibitors and may be used as hits for the development of new drugs against paracoccidioidomycosis.

[Box: see text].

Root Influences Rhizosphere Hydraulic Properties through Soil Organic Carbon and Microbial Activity.

Processes of water retention and movement and the hydraulic conductivity are altered in the rhizosphere. The aim of this study was to investigate the physical-hydric properties of soil aggregates in the rhizosphere of annual ryegrass (Lolium multiflorum) cropped in a Kandiudalfic Eutrudox, taking into account aspects related to soil aggregate stability. Soil aggregates from rhizosphere soil (RZS) and soil between plant rows (SBP) were used to determine soil water retention curves (SWRCs) and saturated hydraulic conductivity (Ksat). In addition, properties related to soil aggregate stability, such as water-dispersible clay, soil organic carbon (SOC), and microbial activity, were also assessed. The higher microbial activity observed in the RZS was facilitated by increased SOC and microbial activity, resulting in improved soil aggregation (less water-dispersible clay). For nearly all measured matric potentials, RZS had a higher water content than SBP. This was attributed to the stability of aggregates, increase in SOC content, and the root exudates, which improved soil water retention. The increase in total porosity in RZS was associated with improved soil aggregation, which prevents deterioration of the soil pore space and results in higher Ksat and hydraulic conductivity as a function of the effective relative saturation in RZS compared to SBP.

Expression and characterization of monofunctional alcohol dehydrogenase enzymes in Clostridium thermocellum.

Clostridium thermocellum is a thermophilic anaerobic bacterium that could be used for cellulosic biofuel production due to its strong native ability to consume cellulose, however its ethanol production ability needs to be improved to enable commercial application. In our previous strain engineering work, we observed a spontaneous mutation in the native adhE gene that reduced ethanol production. Here we attempted to complement this mutation by heterologous expression of 18 different alcohol dehydrogenase (adh) genes. We were able to express all of them successfully in C. thermocellum. Surprisingly, however, none of them increased ethanol production, and several actually decreased it. Our findings contribute to understanding the correlation between C. thermocellum ethanol production and Adh enzyme cofactor preferences. The identification of a set of adh genes that can be successfully expressed in this organism provides a foundation for future investigations into how the properties of Adh enzymes affect ethanol production.

Pheochromocytoma/paraganglioma type 5 syndrome as a cause of secondary hypertension in a Colombian patient: case report / Síndrome de feocromocitoma-paraganglioma de tipo 5 como causa de hipertensión arterial en una paciente colombiana: reporte de caso

Pheochromocytoma is a tumor derived from neural crest cells able to produce sympathomimetic substances and, hence, a particular clinical picture. It is responsible for less than 1% of high blood pressure cases, with an estimated incidence between 0.4 and 0.6 cases per 100,000 people each year, and an average survival of seven years. Pheochromocytoma is a solid tumor with a high genetic component, as heritability can reach 40%. Once diagnosed, its treatment and prognosis are partly conditioned by the associated pathogenic variants that can be documented, especially those related to RET, SDHx, VHL, and NF1 genes. We present the case of a young woman with abdominal pain and high blood pressure, who was found to have a pheochromocytoma. Genetic testing detected a rare and recently discovered pathogenic variant: the SDHA:c.1A>C (p.Met1Leu). The patient responded adequately to the surgical treatment and continued the follow-up without documented recurrences. The diagnostic approach for pheochromocytoma patients must start with a clinical suspicion, followed by metabolite measurement in blood and urine, and finally, imaging. Currently, technology development allows precision medicine applicability. In this case of pheochromocytoma, recent developments in precision medicine resulted in the detection of associated genetic components involving the patient and her family. Adequate screening of the index patient is required for documenting pathogenic variants and better characterizing the disease.

El feocromocitoma es un tumor derivado de las células de la cresta neural con la capacidad de producir sustancias simpaticomiméticas y, por ende, un cuadro clínico particular. Causa menos del 1 % de los casos de hipertensión arterial sistémica y su incidencia se estima entre 0,4 y 0,6 casos por 100.000 personas cada año, con una supervivencia media de siete años. De todos los tumores sólidos, el feocromocitoma tiene un mayor componente genético, que puede heredarse hasta en el 40 % de los casos. Una vez diagnosticada la enfermedad, se debe definir el tratamiento y el pronóstico, en parte condicionados por las variantes genéticas asociadas, en especial RET, SDHx, VHL y NF1. Se presenta el caso de una mujer joven con dolor abdominal e hipertensión arterial sistémica, a quien se le diagnosticó feocromocitoma. Al secuenciar el exoma, se identificó una variante patogénica extremadamente rara y de reciente descubrimiento: SDHA: c.1A>C (p.Met1Leu). La paciente respondió adecuadamente al tratamiento quirúrgico y continuó en seguimiento sin recurrencias. El abordaje diagnóstico de los pacientes con feocromocitoma comienza con la sospecha clínica, seguida de la medición de determinados metabolitos en sangre y orina, y, finalmente, los estudios de imagenología. Los desarrollos tecnológicos actuales permiten la aplicación de la medicina de precisión en este campo. En este caso de feocromocitoma, se identificó un componente genético importante que no solo afecta al paciente, sino también, a sus familiares. La tamización adecuada del caso índice permite identificar mutaciones y caracterizar mejor la enfermedad.

Dichloroacetate for Cancer Treatment: Some Facts and Many Doubts.

Rarely has a chemical elicited as much controversy as dichloroacetate (DCA). DCA was initially considered a dangerous toxic industrial waste product, then a potential treatment for lactic acidosis. However, the main controversies started in 2008 when DCA was found to have anti-cancer effects on experimental animals. These publications showed contradictory results in vivo and in vitro such that a thorough consideration of this compound's in cancer is merited. Despite 50 years of experimentation, DCA's future in therapeutics is uncertain. Without adequate clinical trials and health authorities' approval, DCA has been introduced in off-label cancer treatments in alternative medicine clinics in Canada, Germany, and other European countries. The lack of well-planned clinical trials and its use by people without medical training has discouraged consideration by the scientific community. There are few thorough clinical studies of DCA, and many publications are individual case reports. Case reports of DCA's benefits against cancer have been increasing recently. Furthermore, it has been shown that DCA synergizes with conventional treatments and other repurposable drugs. Beyond the classic DCA target, pyruvate dehydrogenase kinase, new target molecules have also been recently discovered. These findings have renewed interest in DCA. This paper explores whether existing evidence justifies further research on DCA for cancer treatment and it explores the role DCA may play in it.

Competitive oxidation of key pentose phosphate pathway enzymes modulates the fate of intermediates and NAPDH production.

The oxidative phase of the pentose phosphate pathway (PPP) involving the enzymes glucose-6-phosphate dehydrogenase (G6PDH), 6-phosphogluconolactonase (6PGL), and 6-phosphogluconate dehydrogenase (6PGDH), is critical to NADPH generation within cells, with these enzymes catalyzing the conversion of glucose-6-phosphate (G6P) into ribulose-5-phosphate (Ribu5-P). We have previously studied peroxyl radical (ROO•) mediated oxidative inactivation of E. coli G6PDH, 6PGL, and 6PGDH. However, these data were obtained from experiments where each enzyme was independently exposed to ROO•, a condition not reflecting biological reality. In this work we investigated how NADPH production is modulated when these enzymes are jointly exposed to ROO•. Enzyme mixtures (1:1:1 ratio) were exposed to ROO• produced from thermolysis of 100 mM 2,2'-azobis(2-methylpropionamidine) dihydrochloride (AAPH). NADPH was quantified at 340 nm, and protein oxidation analyzed by liquid chromatography with mass spectrometric detection (LC-MS). The data obtained were rationalized using a mathematical model. The mixture of non-oxidized enzymes, G6P and NADP+ generated ∼175 µM NADPH. Computational simulations showed a constant decrease of G6P associated with NADPH formation, consistent with experimental data. When the enzyme mixture was exposed to AAPH (3 h, 37 °C), lower levels of NADPH were detected (∼100 µM) which also fitted with computational simulations. LC-MS analyses indicated modifications at Tyr, Trp, and Met residues but at lower concentrations than detected for the isolated enzymes. Quantification of NADPH generation showed that the pathway activity was not altered during the initial stages of the oxidations, consistent with a buffering role of G6PDH towards inactivation of the oxidative phase of the pathway.

ß-Adrenergic Stimulation-Induced PVAT Dysfunction in Male Sex: A Role for 11ß-Hydroxysteroid Dehydrogenase-1.

Long-term ß-adrenoceptor (ß-AR) stimulation is a pathological mechanism associated with cardiovascular diseases resulting in endothelial and perivascular adipose tissue (PVAT) dysfunction. In this study, we aimed to identify whether ß-adrenergic signaling has a direct effect on PVAT. Thoracic aorta PVAT was obtained from male Wistar rats and cultured ex vivo with the ß-AR agonist isoproterenol (Iso; 1 µM) or vehicle for 24 hours. Conditioned culture medium (CCM) from Iso-treated PVAT induced a marked increase in aorta contractile response, induced oxidative stress, and reduced nitric oxide production in PVAT compared to vehicle. In addition, Iso-treated PVAT and PVAT-derived differentiated adipocytes exhibited higher corticosterone release and protein expression of 11ß-hydroxysteroid dehydrogenase type 1 (11ß-HSD1), an enzyme responsible for de novo synthesis of corticosterone. Macrophages exposed to Iso also exhibited increased corticosterone release in response to ß-AR stimulation. Incubation of Iso-treated PVAT and PVAT-derived differentiated adipocytes with ß3-AR antagonist restored aorta contractile function modulated by Iso-CCM and normalized 11ß-HSD1 protein expression. These results show that ß3-AR signaling leads to upregulation of 11ß-HSD1 in PVAT, thus increasing corticosterone release and contributing to impair the anticontractile function of this tissue.

The familial amyotrophic lateral sclerosis-associated A4V SOD1 mutant is not able to regulate aerobic glycolysis.

Under certain stress conditions, astrocytes operate in aerobic glycolysis, a process controlled by pyruvate dehydrogenase (PDH) inhibition through its E1 α subunit (Pda1) phosphorylation. This supplies lactate to neurons, which save glucose to obtain NADPH to, among other roles, counteract reactive oxygen species. A failure in this metabolic cooperation causes severe damage to neurons. In this work, using humanized Saccharomyces cerevisiae cells in which its endogenous Cu/Zn Superoxide Dismutase (SOD1) was replaced by human ortholog, we investigated the role of human SOD1 (hSOD1) in aerobic glycolysis regulation and its implications to amyotrophic lateral sclerosis (ALS), a neurodegenerative disease. Yeast cells ferment glucose even in the presence of oxygen and switch to respiratory metabolism after glucose exhaustion. However, like cells of SOD1-knockout strain, cells expressing A4V mutant of hSOD1 growing on glucose showed a respiratory phenotype, i.e., low glucose and high oxygen consumptions and low intracellular oxidation levels in response to peroxide stress, contrary to cells expressing wild-type (WT) SOD1 (yeast or human). The A4V mutation in hSOD1 is linked to ALS. In contrast to WT SOD1 strains, PDH activity of both sod1Δ and A4V hSOD1 cells did not change in response to a metabolic shift toward oxidative metabolism, which was associated to lower Pda1 phosphorylation levels under growth on glucose. Taken together, our results suggest that A4V mutant cannot regulate aerobic glycolysis via Pda1 phosphorylation the same way WT hSOD1, which might be linked to problems observed in the motor neurons of ALS patients with the SOD1 A4V mutation.

Kinetics of glucose-6-phosphate dehydrogenase (G6PD) activity during Plasmodium vivax infection: implications for early radical malaria treatment.

BACKGROUND: Plasmodium vivax relapses due to dormant liver hypnozoites can be prevented with primaquine. However, the dose must be adjusted in individuals with glucose-6-phosphate-dehydrogenase (G6PD) deficiency. In French Guiana, assessment of G6PD activity is typically delayed until day (D)14 to avoid the risk if misclassification. This study assessed the kinetics of G6PD activity throughout P. vivax infection to inform the timing of treatment. METHODS: For this retrospective monocentric study, data on G6PD activity between D1 and D28 after treatment initiation with chloroquine or artemisinin-based combination therapy were collected for patients followed at Cayenne Hospital, French Guiana, between January 2018 and December 2020. Patients were divided into three groups based on the number of available G6PD activity assessments: (i) at least two measurements during the P. vivax malaria infection; (ii) two measurements: one during the current infection and one previously; (iii) only one measurement during the malaria infection. RESULTS: In total, 210 patients were included (80, 20 and 110 in groups 1, 2 and 3, respectively). Data from group 1 showed that G6PD activity remained stable in each patient over time (D1, D3, D7, D14, D21, D28). None of the patients with normal G6PD activity during the initial phase (D1-D3) of the malaria episode (n = 44) was categorized as G6PD-deficient at D14. Patients with G6PD activity < 80% at D1 or D3 showed normal activity at D14. Sex and reticulocyte count were statistically associated with G6PD activity variation. In the whole sample (n = 210), no patient had severe G6PD deficiency (< 10%) and only three between 10 and 30%, giving a G6PD deficiency prevalence of 1.4%. Among the 100 patients from group 1 and 2, 30 patients (26.5%) were lost to follow-up before primaquine initiation. CONCLUSIONS: In patients treated for P. vivax infection, G6PD activity did not vary over time. Therefore, G6PD activity on D1 instead of D14 could be used for primaquine dose-adjustment. This could allow earlier radical treatment with primaquine, that could have a public health impact by decreasing early recurrences and patients lost to follow-up before primaquine initiation. This hypothesis needs to be confirmed in larger prospective studies.

The ketone body ß-Hydroxybutyrate as a fuel source of chondrosarcoma cells.

Chondrosarcoma (CS) is a malignant bone tumor arising from cartilage-producing cells. The conventional subtype of CS typically develops within a dense cartilaginous matrix, creating an environment deficient in oxygen and nutrients, necessitating metabolic adaptation to ensure proliferation under stress conditions. Although ketone bodies (KBs) are oxidized by extrahepatic tissue cells such as the heart and brain, specific cancer cells, including CS cells, can undergo ketolysis. In this study, we found that KBs catabolism is activated in CS cells under nutrition-deprivation conditions. Interestingly, cytosolic ß-hydroxybutyrate dehydrogenase 2 (BDH2), rather than mitochondrial BDH1, is expressed in these cells, indicating a specific metabolic adaptation for ketolysis in this bone tumor. The addition of the KB, ß-Hydroxybutyrate (ß-HB) in serum-starved CS cells re-induced the expression of BDH2, along with the key ketolytic enzyme 3-oxoacid CoA-transferase 1 (OXCT1) and monocarboxylate transporter-1 (MCT1). Additionally, internal ß-HB production was quantified in supplied and starved cells, suggesting that CS cells are also capable of ketogenesis alongside ketolysis. These findings unveil a novel metabolic adaptation wherein nutrition-deprived CS cells utilize KBs for energy supply and proliferation.

Síndrome de feocromocitoma-paraganglioma de tipo 5 como causa de hipertensión arterial en una paciente colombiana: reporte de caso / Pheochromocytoma/paraganglioma type 5 syndrome as a cause of secondary hypertension in a Colombian patient: case report

El feocromocitoma es un tumor derivado de las células de la cresta neural con la capacidad de producir sustancias simpaticomiméticas y, por ende, un cuadro clínico particular. Causa menos del 1 % de los casos de hipertensión arterial sistémica y su incidencia se estima entre 0,4 y 0,6 casos por 100.000 personas cada año, con una supervivencia media de siete años. De todos los tumores sólidos, el feocromocitoma tiene un mayor componente genético, que puede heredarse hasta en el 40 % de los casos. Una vez diagnosticada la enfermedad, se debe definir el tratamiento y el pronóstico, en parte condicionados por las variantes genéticas asociadas, en especial RET, SDHx, VHL y NF1.Se presenta el caso de una mujer joven con dolor abdominal e hipertensión arterial sistémica, a quien se le diagnosticó feocromocitoma. Al secuenciar el exoma, se identificó una variante patogénica extremadamente rara y de reciente descubrimiento: SDHA: c.1A>C (p.Met1Leu). La paciente respondió adecuadamente al tratamiento quirúrgico y continuó en seguimiento sin recurrencias.El abordaje diagnóstico de los pacientes con feocromocitoma comienza con la sospecha clínica, seguida de la medición de determinados metabolitos en sangre y orina, y, finalmente, los estudios de imagenología. Los desarrollos tecnológicos actuales permiten la aplicación de la medicina de precisión en este campo. En este caso de feocromocitoma, se identificó un componente genético importante que no solo afecta al paciente, sino también, a sus familiares. La tamización adecuada del caso índice permite identificar mutaciones y caracterizar mejor la enfermedad.

Pheochromocytoma is a tumor derived from neural crest cells able to produce sympathomimetic substances and, hence, a particular clinical picture. It is responsible for less than 1% of high blood pressure cases, with an estimated incidence between 0.4 and 0.6 cases per 100,000 people each year, and an average survival of seven years. Pheochromocytoma is a solid tumor with a high genetic component, as heritability can reach 40%. Once diagnosed, its treatment and prognosis are partly conditioned by the associated pathogenic variants that can be documented, especially those related to RET, SDHx, VHL, and NF1 genes.We present the case of a young woman with abdominal pain and high blood pressure, who was found to have a pheochromocytoma. Genetic testing detected a rare and recently discovered pathogenic variant: the SDHA:c.1A>C (p.Met1Leu). The patient responded adequately to the surgical treatment and continued the follow-up without documented recurrences.The diagnostic approach for pheochromocytoma patients must start with a clinical suspicion, followed by metabolite measurement in blood and urine, and finally, imaging. Currently, technology development allows precision medicine applicability. In this case of pheochromocytoma, recent developments in precision medicine resulted in the detection of associated genetic components involving the patient and her family. Adequate screening of the index patient is required for documenting pathogenic variants and better characterizing the disease.

Anandamide and WIN 55212-2 Afford Protection in Rat Brain Mitochondria in a Toxic Model Induced by 3-Nitropropionic Acid: an In Vitro Study.

Mitochondrial dysfunction plays a key role in the development of neurodegenerative disorders. In contrast, the regulation of the endocannabinoid system has been shown to promote neuroprotection in different neurotoxic paradigms. The existence of an active form of the cannabinoid receptor 1 (CB1R) in mitochondrial membranes (mitCB1R), which might exert its effects through the same signaling mechanisms as the cell membrane CB1R, has been shown to regulate mitochondrial activity. Although there is evidence suggesting that some cannabinoids may induce protective effects on isolated mitochondria, substantial evidence on the role of cannabinoids in mitochondria remains to be explored. In this work, we developed a toxic model of mitochondrial dysfunction induced by exposure of brain mitochondria to the succinate dehydrogenase inhibitor 3-nitropropionic acid (3-NP). Mitochondria were also pre-incubated with the endogenous agonist anandamide (AEA) and the synthetic CB1R agonist WIN 55212-2 to evaluate their protective effects. Mitochondrial reduction capacity, reactive oxygen species (ROS) formation, and mitochondrial swelling were assessed as toxic markers. While 3-NP decreased the mitochondrial reduction capacity and augmented mitochondrial ROS formation and swelling, both AEA and WIN 55212-2 ameliorated these toxic effects. To explore the possible involvement of mitCB1R activation on the protective effects of AEA and WIN 55212-2, mitochondria were also pre-incubated in the presence of the selective CB1R antagonist AM281, which completely reverted the protective effects of the cannabinoids to levels similar to those evoked by 3-NP. These results show partial protective effects of cannabinoids, suggesting that mitCB1R activation may be involved in the recovery of compromised mitochondrial activity, related to reduction of ROS formation and further prevention of mitochondrial swelling.

Structural insights into the Smirnoff-Wheeler pathway for vitamin C production in the Amazon fruit camu-camu.

l-Ascorbic acid (AsA, vitamin C) is a pivotal dietary nutrient with multifaceted importance in living organisms. In plants, the Smirnoff-Wheeler pathway is the primary route for AsA biosynthesis, and understanding the mechanistic details behind its component enzymes has implications for plant biology, nutritional science, and biotechnology. As part of an initiative to determine the structures of all six core enzymes of the pathway, the present study focuses on three of them in the model species Myrciaria dubia (camu-camu): GDP-d-mannose 3',5'-epimerase (GME), l-galactose dehydrogenase (l-GalDH), and l-galactono-1,4-lactone dehydrogenase (l-GalLDH). We provide insights into substrate and cofactor binding and the conformational changes they induce. The MdGME structure reveals a distorted substrate in the active site, pertinent to the catalytic mechanism. Mdl-GalDH shows that the way in which NAD+ association affects loop structure over the active site is not conserved when compared with its homologue in spinach. Finally, the structure of Mdl-GalLDH is described for the first time. This allows for the rationalization of previously identified residues which play important roles in the active site or in the formation of the covalent bond with FAD. In conclusion, this study enhances our understanding of AsA biosynthesis in plants, and the information provided should prove useful for biotechnological applications.

Oxidase enzyme genes are differentially expressed during Acanthamoeba castellanii encystment.

Acanthamoeba castellanii, a ubiquitous protozoan, is responsible for significant diseases such as Acanthamoeba keratitis and granulomatous amoebic encephalitis. A crucial survival strategy of A. castellanii involves the formation of highly resistant cysts during adverse conditions. This study delves into the cellular processes underpinning encystment, focusing on gene expression changes related to reactive oxygen species (ROS) balance, with a particular emphasis on mitochondrial processes. Our findings reveal a dynamic response within the mitochondria during encystment, with the downregulation of key enzymes involved in oxidative phosphorylation (COX, AOX, and NADHalt) during the initial 48 h, followed by their overexpression at 72 h. This orchestrated response likely creates a pro-oxidative environment, facilitating encystment. Analysis of other ROS processing enzymes across the cell reveals differential expression patterns. Notably, antioxidant enzymes, such as catalases, glutaredoxins, glutathione S-transferases, peroxiredoxins, and thioredoxins, mirror the mitochondrial trend of downregulation followed by upregulation. Additionally, glycolysis and gluconeogenesis are downregulated during the early stages in order to potentially balance the metabolic requirement of the cyst. Our study underscores the importance of ROS regulation in Acanthamoeba encystment. Understanding these mechanisms offers insights into infection control and identifies potential therapeutic targets. This work contributes to unraveling the complex biology of A. castellanii and may aid in combatting Acanthamoeba-related infections. Further research into ROS and oxidase enzymes is warranted, given the organism's remarkable respiratory versatility.

Structure of glyceraldehyde-3-phosphate dehydrogenase from Paracoccidioides lutzii in complex with an aldonic sugar acid.

The pathogen Paracoccidioides lutzii (Pb01) is found in South America countries Colombia, Ecuador, Venezuela and Brazil, especially in the central, west, and north regions of the latter. It belongs to the Ajellomycetaceae family, Onygenales order, and is typically thermodimorphic, presenting yeast cells when it grows in animal tissues, but mycelia when in the environment, where it produces the infectious propagule. This fungus is one of the etiologic agents of Paracoccidioidomycosis (PCM), the most important endemic fungal infection in Latin America. Investigations on its genome have contributed to a better understanding about its metabolism and revealed the complexity of several metabolic glycolytic pathways. Glyceraldehyde-3-Phosphate Dehydrogenase from Paracoccidioides lutzii (PlGAPDH) is considered a moonlighting protein and participates in several biological processes of this pathogen. The enzyme was expressed and purified, as seen in SDS-PAGE gel, crystallized and had its three dimensional structure (3D) determined in complex with NAD+, a sulphate ion and d-galactonic acid, therefore, a type of 'GAA site'. It is the first GAPDH structure to show this chemical type in this site and how this protein can bind an acid derived from oxidation of a linear hexose.

Lipid signaling and proline catabolism are activated in barley roots (Hordeum vulgare L.) during recovery from cold stress.

Previous findings have shown that phospholipase D (PLD) contributes to the response to long-term chilling stress in barley by regulating the balance of proline (Pro) levels. Although Pro accumulation is one of the most prominent changes in barley roots exposed to this kind of stress, the regulation of its metabolism during recovery from stress remains unclear. Research has mostly focused on the responses to stress per se, and not much is known about the dynamics and mechanisms underlying the subsequent recovery. The present study aimed to evaluate how PLD, its product phosphatidic acid (PA), and diacylglycerol pyrophosphate (DGPP) modulate Pro accumulation in barley during recovery from long-term chilling stress. Pro metabolism involves different pathways and enzymes. The rate-limiting step is mediated by pyrroline-5-carboxylate synthetase (P5CS) in its biosynthesis, and by proline dehydrogenase (ProDH) in its catabolism. We observed that Pro levels decreased in recovering barley roots due to an increase in ProDH activity. The addition of 1-butanol, a PLD inhibitor, reverted this effect and altered the relative gene expression of ProDH. When barley tissues were treated with PA before recovery, the fresh weight of roots increased and ProDH activity was stimulated. These data contribute to our understanding of how acidic membrane phospholipids like PA help to control Pro degradation during recovery from stress.

Evaluation of glial tumors: correlation between magnetic resonance imaging and histopathological analysis / Avaliação de tumores gliais por ressonância magnética e correlação com estudo histopatológico

Abstract Objective: To determine the correlation of conventional and diffusion-weighted imaging findings on magnetic resonance imaging (MRI) of the brain, based on Visually AcceSAble Rembrandt Images (VASARI) criteria, with the histopathological grading of gliomas: low-grade or high-grade. Materials and Methods: Preoperative MRI scans of 178 patients with brain gliomas and pathological confirmation were rated by two neuroradiologists for tumor size, location, and tumor morphology, using a standardized imaging feature set based on the VASARI criteria. Results: In the univariate analysis, more than half of the MRI characteristics evaluated showed a significant association with the tumor grade. The characteristics most significantly associated with the tumor grade were hemorrhage; restricted diffusion; pial invasion; enhancement; and a non-contrast-enhancing tumor crossing the midline. In a multivariable regression model, the presence of enhancement and hemorrhage maintained a significant association with high tumor grade. The absence of contrast enhancement and restricted diffusion were associated with the presence of an isocitrate dehydrogenase gene mutation. Conclusion: Our data illustrate that VASARI MRI features, especially intratumoral hemorrhage, contrast enhancement, and multicentricity, correlate strongly with glial tumor grade.

Resumo Objetivo: Determinar a correlação dos achados de imagem convencional e de difusão na ressonância magnética (RM) do encéfalo, com base nos critérios Visually AcceSAble Rembrandt Images (VASARI), com a classificação histopatológica de gliomas: gliomas de baixo grau e gliomas de alto grau. Materiais e Métodos: Imagens de RM pré-cirúrgicas de 178 pacientes com gliomas cerebrais e confirmação patológica foram avaliadas por dois neurorradiologistas quanto ao tamanho, localização e morfologia do tumor usando um padrão de imagem baseado nos critérios VASARI. Resultados: Na análise univariada, mais da metade das características avaliadas apresentou associação significativa com o grau do tumor. Hemorragia, restrição à difusão, invasão pial, realce e tumor sem realce cruzando a linha média foram as características com associação mais significativa. No modelo de regressão multivariada, a presença de realce e hemorragia manteve associação significativa com tumores de alto grau. A ausência de realce pelo meio de contraste e a restrição da difusão foram associados à presença da mutação do gene isocitrato desidrogenase. Conclusão: Nossos dados ilustram que as características de RM do VASARI, especialmente hemorragia intratumoral, presença de realce de contraste e multicentricidade, forneceram uma correlação importante com o grau da neoplasia glial.

Medium Chain Acyl CoA Dehydrogenase Deficiency and Eating Disorders: An Underreported Coincidence

Abstract Medium chain acyl-coA dehydrogenase deficiency (MCADD), the most common fatty acid oxidation disorder, has been regarded as a relatively benign condition with low risk of mortality in patients with a known diagnosis, if adequate caloric intake is met. However, inadequate energy provision, as occurs in eating disorders, significantly amplifies the risk of metabolic decompensation. This case series describes four patients with MCADD and a concomitant eating disorder and aims to raise awareness of the potentially under-recognised coexistence of these conditions. All patients were female with signs of disordered eating in adolescence and young adulthood though latency in diagnosis was apparent. Three of the patients had low body mass index (BMI) and the other was overweight. Metabolic decompensation and hospitalisation occurred in three of four patients secondary to extreme risk-taking behaviour with caloric restriction. The coexistence of MCADD and eating disorders is of significant concern, placing the patient at substantial risk of decompensation in an otherwise relatively stable metabolic condition. Awareness of disordered eating in this population is paramount, as early recognition of signs and symptoms of eating disorders in the MCADD population may facilitate prompt intervention and avoidance of morbidity and potential mortality.