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Keywords = AOX prediction

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18 pages, 12199 KiB  
Article
Impairment of Muscle Function Causes Pupal Lethality in Flies Expressing the Mitochondrial Alternative Oxidase
by Carlos A. Couto-Lima, Sina Saari, Geovana S. Garcia, Gabriel H. Rocha, Johanna ten Hoeve, Eric Dufour and Marcos T. Oliveira
Biomolecules 2025, 15(4), 570; https://doi.org/10.3390/biom15040570 - 11 Apr 2025
Viewed by 634
Abstract
The mitochondrial alternative oxidase (AOX) from the tunicate Ciona intestinalis has been explored as a potential therapeutic enzyme for human mitochondrial diseases, yet its systemic effects remain poorly understood. Here, we investigate the metabolic and physiological consequences of AOX expression during the development [...] Read more.
The mitochondrial alternative oxidase (AOX) from the tunicate Ciona intestinalis has been explored as a potential therapeutic enzyme for human mitochondrial diseases, yet its systemic effects remain poorly understood. Here, we investigate the metabolic and physiological consequences of AOX expression during the development of Drosophila cultured under dietary stress. We show that the combination of strong, ubiquitous AOX expression and a low-nutrient condition leads to pupal lethality and severe defects in larval musculature, characterized by actin aggregation and muscle shortening. These structural abnormalities correlate with a decrease in larval biomass and motility. Interestingly, the muscle defects and the motility impairments vary in severity among individuals, predicting survival rates at the pupal stage. AOX expression in specific tissues (muscle, nervous system or fat body) does not individually recapitulate the lethal phenotype observed with ubiquitous expressions of the enzyme, indicating a complex metabolic imbalance. Metabolomic analysis revealed that the low-nutrient diet and AOX expression have opposite effects on most metabolites analyzed, especially in the levels of amino acids. Notably, supplementation of the low-nutrient diet with the essential amino acids methionine and/or tryptophan partially rescues pupal viability, body size, muscle morphology, and locomotion, whereas supplementation with proline and/or glutamate does not, highlighting a specific perturbation in amino acid metabolism rather than general bioenergetic depletion. These findings demonstrate that AOX expression disrupts metabolic homeostasis, with developmental and physiological consequences that must be considered when evaluating AOX for therapeutic applications. Full article
(This article belongs to the Special Issue Drosophila as a Model System to Study Metabolism)
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14 pages, 1065 KiB  
Article
Interrelationships Among Sensitivity, Precision, Accuracy, Specificity and Predictive Values in Bioassays, Represented as Combined ROC Curves with Integrated Cutoff Distribution Curves and Novel Index Values
by Peter Oehr
Diagnostics 2025, 15(4), 410; https://doi.org/10.3390/diagnostics15040410 - 7 Feb 2025
Viewed by 1600
Abstract
Background/Objectives: This work introduces accuracy- and precision-ROC curves in addition to SS– and PV–ROC curves and shows a novel means of profiling biomarker characteristics for validation of optimal cutoffs in clinical diagnostics and decision making. Methods: This investigation included 91 patients with a [...] Read more.
Background/Objectives: This work introduces accuracy- and precision-ROC curves in addition to SS– and PV–ROC curves and shows a novel means of profiling biomarker characteristics for validation of optimal cutoffs in clinical diagnostics and decision making. Methods: This investigation included 91 patients with a confirmed bladder cancer diagnosis and 1152 patients without evidence of cancer. The study performed a quantitative investigation of used-up test cassettes from the visual UBC® Rapid qualitative point-of-care assay, which had already been applied in routine diagnostics. Using a photometric reader, quantitative data could also be obtained from the test line of the used cassettes. The ROC curves were constructed using different thresholds or cutoff levels to determine the TP/TN and FP/FN values for each threshold at concentrations of 5, 10, 30, 50, 90, 110, 250 and 300 µg/L. The resulting TP/TN and FP/FN values were used to calculate the sensitivity/specificity, accuracy, precision and predictive values in order to plot the ROC curves with integrated cutoff value distributions and their index cutoff diagrams. Results: A common, optimal cutoff value for all the diagnostic parameters was derived with the aid of an ROC index cutoff diagram. It includes higher specificity and an acceptable number of NPVs. As a result, use of a sensitivity–specificity ROC curve and the Youden index only permits the selection of a maximal threshold value or cutoff point for the biomarker of interest but disregards the clinical status of the patient, whereas the precision, accuracy and predictive values give information related to the disease. Conclusions: This work’s novelty compared to the existing methodology includes the first international publication of accuracy- and precision-ROC curves. It enables the investigation of the relationship among the sensitivity, specificity, precision, accuracy and predictive values at varied cutoff levels within a bioassay, presenting these in a single graph consisting of selected receiver operating characteristic (ROC) curves for each parameter, including cutoff distribution curves. This is a transparent method to identify appropriate cutoffs for multiple diagnostic parameters. According to the results, the single-sided use of a sensitivity–specificity ROC curve including the maximal Youden index value as an optimal cutoff or single-point determinations for predictive values cannot provide diagnostic information of the same quality as that given by a multi-parameter diagnostic profile and a multi-parameter cutoff-index-diagram-derived optimal value as presented within this work. The proposed multi-parameter cutoff-index diagram includes novel index cutoff AOX. It is a new different method that allows a quantitative comparison of the results from multi-parameter ROC curves, which cannot be performed with the AUC. However, the methods are different and do not exclude each other. Full article
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20 pages, 4752 KiB  
Article
Genome-Wide Identification and Characterization of Alternative Oxidase (AOX) Genes in Foxtail Millet (Setaria italica): Insights into Their Abiotic Stress Response
by Hui Zhang, Yidan Luo, Yujing Wang, Juan Zhao, Yueyue Wang, Yajun Li, Yihao Pu, Xingchun Wang, Xuemei Ren and Bo Zhao
Plants 2024, 13(18), 2565; https://doi.org/10.3390/plants13182565 - 12 Sep 2024
Cited by 2 | Viewed by 1631
Abstract
Alternative oxidase (AOX) serves as a critical terminal oxidase within the plant respiratory pathway, playing a significant role in cellular responses to various stresses. Foxtail millet (Setaria italica), a crop extensively cultivated across Asia, is renowned for its remarkable [...] Read more.
Alternative oxidase (AOX) serves as a critical terminal oxidase within the plant respiratory pathway, playing a significant role in cellular responses to various stresses. Foxtail millet (Setaria italica), a crop extensively cultivated across Asia, is renowned for its remarkable tolerance to abiotic stresses and minimal requirement for fertilizer. In this study, we conducted a comprehensive genome-wide identification of AOX genes in foxtail millet genome, discovering a total of five SiAOX genes. Phylogenetic analysis categorized these SiAOX members into two subgroups. Prediction of cis-elements within the promoter regions, coupled with co-expression network analysis, intimated that SiAOX proteins are likely involved in the plant’s adaptive response to abiotic stresses. Employing RNA sequencing (RNA-seq) and real-time quantitative PCR (RT-qPCR), we scrutinized the expression patterns of the SiAOX genes across a variety of tissues and under multiple abiotic stress conditions. Specifically, our analysis uncovered that SiAOX1, SiAOX2, SiAOX4, and SiAOX5 display distinct tissue-specific expression profiles. Furthermore, SiAOX2, SiAOX3, SiAOX4, and SiAOX5 exhibit responsive expression patterns under abiotic stress conditions, with significant differences in expression levels observed between the shoot and root tissues of foxtail millet seedlings. Haplotype analysis of SiAOX4 and SiAOX5 revealed that these genes are in linkage disequilibrium, with Hap_2 being the superior haplotype for both, potentially conferring enhanced cold stress tolerance in the cultivar group. These findings suggest that both SiAOX4 and SiAOX5 may be targeted for selection in future breeding programs aimed at improving foxtail millet’s resilience to cold stress. Full article
(This article belongs to the Section Plant Molecular Biology)
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15 pages, 4523 KiB  
Article
Effect of Partial Elimination of Mitochondrial DNA on Genome-Wide Identified AOX Gene Family in Chlamydomonas reinhardtii
by Asadullah Khan, Zuo Jihong, Haolin Luo, Ali Raza, Quaid Hussain and Zhangli Hu
Processes 2024, 12(8), 1654; https://doi.org/10.3390/pr12081654 - 7 Aug 2024
Cited by 2 | Viewed by 1644
Abstract
Using Chlamydomonas as a model organism, we attempted to eliminate mitochondrial DNA (mtDNA) similar to rho0 or rho cells (completely or partially mtDNA-eliminated cells) in yeast. We successfully generated partially mtDNA-eliminated cells named as crm- cells, causing the inactivation of mitochondrial [...] Read more.
Using Chlamydomonas as a model organism, we attempted to eliminate mitochondrial DNA (mtDNA) similar to rho0 or rho cells (completely or partially mtDNA-eliminated cells) in yeast. We successfully generated partially mtDNA-eliminated cells named as crm- cells, causing the inactivation of mitochondrial activity. We used three different chemicals to eliminate mtDNA including acriflavine (AF), ethidium bromide (EB) and dideoxycytidine (ddC) which prevents replication, inhibits POLG (DNA polymerase gamma) and terminates the mtDNA chain, respectively. The qPCR method was used to detect the mtDNA copy number and the selected rrnL6 gene for the detection of mitochondria, as well as the selected Chlamydomonas CC-124 strain. A reduction in the mitochondrial copy number led to a higher expression of AOX1, UCP1, PGRL1 and ICL1, which indicates the disturbance of the mitochondria–chloroplast ATP and NADPH balance. We selected AOX genes to further study this family and carried out a genome-wide search to identify AOX genes in green algae (C. reinhardtii). Our results revealed that C. reinhardtii contains four AOX genes, i.e., CrAOX1, CrAOX2, CrAOX3 and CrAOX4, which are distributed on Chr 3, Chr7 and Chr9. All CrAOX genes were predicted to localize in mitochondria using bioinformatics tools. Phylogenetic analysis suggests that these CrAOXs are subdivided into four groups and genes existing in the same group could perform identical functions. Collinearity analysis describes the strong evolutionary relationships of AOXs between the unicellular green algae Chlamydomonas reinhardtii and the multicellular green algae Volvox carteri. GO (gene ontology) annotation analysis predicted that CrAOXs played an integral part in carrying out alternate oxidative and respirative activities. Three putative miRNAs, cre-miR1162-3p, cre-miR1171 and cre-miR914, targeting the CrAOX2 gene were identified. Our studies have laid a foundation for the further use of partially mtDNA-eliminated cells and elucidating the functional characteristics of the AOX gene family. Full article
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18 pages, 3985 KiB  
Article
Novel Tools for Single Comparative and Unified Evaluation of Qualitative and Quantitative Bioassays: SS/PV–ROC and SS-J/PV-PSI Index–ROC Curves with Integrated Concentration Distributions, and SS-J/PV-PSI Index Cut-Off Diagrams
by Peter Oehr
Diagnostics 2024, 14(9), 951; https://doi.org/10.3390/diagnostics14090951 - 30 Apr 2024
Cited by 2 | Viewed by 2005
Abstract
Background: This investigation is both a study of potential non-invasive diagnostic approaches for the bladder cancer biomarker UBC® Rapid test and a study including novel comparative methods for bioassay evaluation and comparison that uses bladder cancer as a useful example. The objective [...] Read more.
Background: This investigation is both a study of potential non-invasive diagnostic approaches for the bladder cancer biomarker UBC® Rapid test and a study including novel comparative methods for bioassay evaluation and comparison that uses bladder cancer as a useful example. The objective of the paper is not to investigate specific data. It is used only for demonstration, partially to compare ROC methodologies and also to show how both sensitivity/specificity and predictive values can be used in clinical diagnostics and decision making. This study includes ROC curves with integrated cut-off distribution curves for a comparison of sensitivity/specificity (SS) and positive/negative predictive values (PPV/NPV or PV), as well as SS-J index/PV-PSI index–ROC curves and SS-J/PV-PSI index cut-off diagrams (J = Youden, PSI = Predictive Summary Index) for the unified direct comparison of SS-J/PV results achieved via quantitative and/or qualitative bioassays and an identification of optimal separate or unified index cut-off points. Patients and Methods: According to the routine diagnostics, there were 91 patients with confirmed bladder cancer and 1152 patients with no evidence of bladder cancer, leading to a prevalence value of 0.073. This study performed a quantitative investigation of used-up test cassettes from the visual UBC® Rapid qualitative point-of-care assay, which had already been applied in routine diagnostics. Using a photometric reader, quantitative data could also be obtained from the test line of the used cassettes. Interrelations between SS and PV values were evaluated using cumulative distribution analysis (CAD), SS/PV–ROC curves, SS-J/PV-PSI index–ROC curves, and the SS-J/PV-PSI index cut-off diagram. The maximum unified SS-J/PV-PSI index value and its corresponding cut-off value were determined and calculated with the SS-J/PV-PSI index cut-off diagram. Results: The use of SS/PV–ROC curves with integrated cut-off concentration distribution curves provides improved diagnostic information compared to “traditional” ROC curves. The threshold distributions integrated as curves into SS/PV–ROC curves and SS-J/PV-PSI index–ROC curves run in opposite directions. In contrast to the SS–ROC curves, the PV–ROC and the novel PV-PSI index–ROC curves had neither an area under the curve (AUC) nor a range from 0% to 100%. The cut-off level of the qualitative assay was 7.5 µg/L, with a sensitivity of 65.9% and a specificity of 63.3%, and the PPV was 12.4% and the NPV was 95.9%, at a threshold value of 12.5 µg/L. Based on these set concentrations, the reader-based evaluation revealed a graphically estimated 5% increase in sensitivity and a 13% increase in specificity, as compared to the visual qualitative POC test. In the case of predictive values, there was a gain of 8% for PPV and 10% for NPV. The index values and cut-offs were as follows: visual SS-J index, 0.328 and 35 µg/L; visual PV-PSI index, 0.083 and 5.4 µg/L; maximal reader Youden index, 0.0558 and 250 µg/L; and maximal PV-PSI index, 0.459 and 250 µg/L, respectively. The maximum unified SS-J/PV-PSI index value was 0.32, and the cut-off was 43 µg/L. The reciprocal SS-J index correctly detected one out of three patients, while the reciprocal PV-PSI index gave one out of twelve patients a correct diagnosis. Conclusions: ROC curves including cut-off distribution curves supplement the information lost in “traditionally plotted” ROC curves. The novel sets of ROC and index–ROC curves and the new SS/PV index cut-off diagrams enable the simultaneous comparison of sensitivity/specificity and predictive value profiles of diagnostic tools and the identification of optimal cut-off values at maximal index values, even in a unifying SS/PV approach. Because the curves within an SS-J/PV-PSI index cut-off diagram are distributed over the complete cut-off range of a quantitative assay, this field is open for special clinical considerations, with the need to vary the mentioned clinical diagnostic parameters. Complete or partial areas over the x-axis (AOX) can be calculated for summarized quantitative or qualitative effectivity evaluations with respect to single and/or unified SS-J and PV-PSI indices and with respect to single, several, or several unified assays. The SS-J/PV-PSI index-AOX approach is a new tool providing additional joint clinical information, and the reciprocal SS-J indices can predict the number of patients with a correct diagnosis and the number of persons who need to be examined in order to correctly predict a diagnosis of the disease. These methods could be used in applications like medical or plant epidemiology, machine learning algorithms, and neural networks. Full article
(This article belongs to the Section Clinical Laboratory Medicine)
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25 pages, 4129 KiB  
Article
Transcriptome Analyses in Adult Olive Trees Indicate Acetaldehyde Release and Cyanide-Mediated Respiration Traits as Critical for Tolerance against Xylella fastidiosa and Suggest AOX Gene Family as Marker for Multiple-Resilience
by Birgit Arnholdt-Schmitt, Debabrata Sircar, Shahid Aziz, Thais Andrade Germano, Karine Leitão Lima Thiers, Carlos Noceda, Revuru Bharadwaj, Gunasekaran Mohanapriya and José Hélio Costa
Pathogens 2024, 13(3), 227; https://doi.org/10.3390/pathogens13030227 - 5 Mar 2024
Cited by 4 | Viewed by 2498
Abstract
Xylella fastidiosa (Xf) is a global bacterial threat for a diversity of plants, including olive trees. However, current understanding of host responses upon Xf-infection is limited to allow early disease prediction, diagnosis, and sustainable strategies for breeding on plant tolerance. [...] Read more.
Xylella fastidiosa (Xf) is a global bacterial threat for a diversity of plants, including olive trees. However, current understanding of host responses upon Xf-infection is limited to allow early disease prediction, diagnosis, and sustainable strategies for breeding on plant tolerance. Recently, we identified a major complex trait for early de novo programming, named CoV-MAC-TED, by comparing early transcriptome data during plant cell survival with SARS-CoV-2-infected human cells. This trait linked ROS/RNS balancing during first hours of stress perception with increased aerobic fermentation connected to alpha-tubulin-based cell restructuration and control of cell cycle progression. Furthermore, our group had advanced concepts and strategies for breeding on plant holobionts. Here, we studied tolerance against Xf-infection by applying a CoV-MAC-TED-related gene set to (1) progress proof-of-principles, (2) highlight the importance of individual host responses for knowledge gain, (3) benefit sustainable production of Xf-threatened olive, (4) stimulate new thinking on principle roles of secondary metabolite synthesis and microbiota for system equilibration and, (5) advance functional marker development for resilience prediction including tolerance to Xf-infections. We performed hypothesis-driven complex analyses in an open access transcriptome of primary target xylem tissues of naturally Xf-infected olive trees of the Xf-tolerant cv. Leccino and the Xf-susceptible cv. Ogliarola. The results indicated that cyanide-mediated equilibration of oxygen-dependent respiration and carbon-stress alleviation by the help of increased glycolysis-driven aerobic fermentation paths and phenolic metabolism associate to tolerance against Xf. Furthermore, enhanced alternative oxidase (AOX) transcript levels through transcription Gleichschaltung linked to quinic acid synthesis appeared as promising trait for functional marker development. Moreover, the results support the idea that fungal endophytes strengthen Xf-susceptible genotypes, which lack efficient AOX functionality. Overall, this proof-of-principles approach supports the idea that efficient regulation of the multi-functional AOX gene family can assist selection on multiple-resilience, which integrates Xf-tolerance, and stimulates future validation across diverse systems. Full article
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19 pages, 16076 KiB  
Article
Novel Insights into the Circadian Rhythms Based on Long Noncoding and Circular RNA Profiling
by Xiaodong Tan, Jiawen Zhang, Jie Dong, Minjie Huang, Zhenzhen Zhou and Deqian Wang
Int. J. Mol. Sci. 2024, 25(2), 1161; https://doi.org/10.3390/ijms25021161 - 18 Jan 2024
Cited by 1 | Viewed by 2046
Abstract
Circadian rhythm disorders pose major risks to human health and animal production activity, and the hypothalamus is the center of circadian rhythm regulation. However, the epigenetic regulation of circadian rhythm based on farm animal models has been poorly investigated. We collected chicken hypothalamus [...] Read more.
Circadian rhythm disorders pose major risks to human health and animal production activity, and the hypothalamus is the center of circadian rhythm regulation. However, the epigenetic regulation of circadian rhythm based on farm animal models has been poorly investigated. We collected chicken hypothalamus samples at seven time points in one light/dark cycle and performed long noncoding RNA (lncRNA), circular RNA (circRNA), and mRNA sequencing to detect biomarkers associated with circadian rhythm. We enhanced the comprehensive expression profiling of ncRNAs and mRNAs in the hypothalamus and found two gene sets (circadian rhythm and retinal metabolism) associated with the light/dark cycle. Noncoding RNA networks with circadian expression patterns were identified by differential expression and circadian analysis was provided that included 38 lncRNAs, 15 circRNAs, and 200 candidate genes. Three lncRNAs (ENSGALT00000098661, ENSGALT00000100816, and MSTRG.16980.1) and one circRNA (novel_circ_010168) in the ncRNA–mRNA regulatory network were identified as key molecules influencing circadian rhythm by regulating AOX1 in retinal metabolism. These ncRNAs were predicted to be related to pernicious anemia, gonadal, eye disease and other disorders in humans. Together, the findings of this study provide insights into the epigenetic mechanisms of circadian rhythm and reveal AOX1 as a promising target of circadian rhythm regulation. Full article
(This article belongs to the Section Molecular Biology)
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13 pages, 5382 KiB  
Article
The Effects of Nine Compounds on Aldehyde-Oxidase-Related Genes in Bactrocera dorsalis (Hendel)
by Yan Zou, Yupeng Chen, Duoduo Wang, Xiaowei Xie, Gen Li, Chunyan Zheng, Jian Wen, Hongai Su, Xin Liu, Ling Zeng, Yongyue Lu and Fengqin Cao
Genes 2024, 15(1), 35; https://doi.org/10.3390/genes15010035 - 25 Dec 2023
Cited by 2 | Viewed by 1948
Abstract
Bactrocera dorsalis (Hendel) (Diptera: Tephritidae) (B. dorsalis) is an important agricultural, major invasive, and quarantine pest that can cause significant damage to the economic value of the fruit and vegetable industry. Male bait is one of the most effective methods of [...] Read more.
Bactrocera dorsalis (Hendel) (Diptera: Tephritidae) (B. dorsalis) is an important agricultural, major invasive, and quarantine pest that can cause significant damage to the economic value of the fruit and vegetable industry. Male bait is one of the most effective methods of surveying, monitoring, and controlling B. dorsalis. In our study, we constructed cDNA libraries using total RNA extracted independently from the antennae, mouthparts, and thoracic legs of male and female adults and the ovipositors of female adults and screened out four aldehyde-oxidase-related genes (AOX-related), C58800, C66700, C67485, and C67698. Molecular docking predictions showed that eight compounds, including 3,4-dimethoxycinnamyl alcohol, 3,4-dimethoxy-cinnamaldehyde, deet, ethyl N-acetyl-N-butyl-β-alaninate, n-butyl butyrate, n-butyl butyrate, ethyl butyrate, methyl eugenol, and ethyl acetate, could combine with proteins encoded by the four B. dorsalis AOX-related genes. Furthermore, QPCR was performed to confirm that four compounds, including 3,4-dimethoxy cinnamic aldehyde, butyl levulinic acid ethyl ester (mosquito repellent), butyl butyrate, and methyl eugenol, induced significant changes in the AOX-related genes of B. dorsalis. These results provide useful information and guidance for the batch screening of potentially useful compounds and the search for effective attractants of B. dorsalis. Full article
(This article belongs to the Section Molecular Genetics and Genomics)
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17 pages, 5913 KiB  
Article
In Silico Prediction of Metabolic Reaction Catalyzed by Human Aldehyde Oxidase
by Mengting Huang, Keyun Zhu, Yimeng Wang, Chaofeng Lou, Huimin Sun, Weihua Li, Yun Tang and Guixia Liu
Metabolites 2023, 13(3), 449; https://doi.org/10.3390/metabo13030449 - 19 Mar 2023
Cited by 1 | Viewed by 2696
Abstract
Aldehyde oxidase (AOX) plays an important role in drug metabolism. Human AOX (hAOX) is widely distributed in the body, and there are some differences between species. Currently, animal models cannot accurately predict the metabolism of hAOX. Therefore, more and more in silico models [...] Read more.
Aldehyde oxidase (AOX) plays an important role in drug metabolism. Human AOX (hAOX) is widely distributed in the body, and there are some differences between species. Currently, animal models cannot accurately predict the metabolism of hAOX. Therefore, more and more in silico models have been constructed for the prediction of the hAOX metabolism. These models are based on molecular docking and quantum chemistry theory, which are time-consuming and difficult to automate. Therefore, in this study, we compared traditional machine learning methods, graph convolutional neural network methods, and sequence-based methods with limited data, and proposed a ligand-based model for the metabolism prediction catalyzed by hAOX. Compared with the published models, our model achieved better performance (ACC = 0.91, F1 = 0.77). What’s more, we built a web server to predict the sites of metabolism (SOMs) for hAOX. In summary, this study provides a convenient and automatable model and builds a web server named Meta-hAOX for accelerating the drug design and optimization stage. Full article
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20 pages, 4250 KiB  
Article
Effects of Temperature, pH, and NaCl Concentration on Biomass and Bioactive Compound Production by Synechocystis salina
by Joana Assunção, Helena M. Amaro, Tânia Tavares, F. Xavier Malcata and A. Catarina Guedes
Life 2023, 13(1), 187; https://doi.org/10.3390/life13010187 - 9 Jan 2023
Cited by 8 | Viewed by 3344
Abstract
Synechocystis salina is a cyanobacterium that has biotechnological potential thanks to its ability to synthesize several bioactive compounds of interest. Therefore, this study aimed to find optimal conditions, in terms of temperature (15–25 °C), pH (6.5–9.5), and NaCl concentration (10–40 g·L−1), [...] Read more.
Synechocystis salina is a cyanobacterium that has biotechnological potential thanks to its ability to synthesize several bioactive compounds of interest. Therefore, this study aimed to find optimal conditions, in terms of temperature (15–25 °C), pH (6.5–9.5), and NaCl concentration (10–40 g·L−1), using as objective functions the productivities of biomass, total carotenoids, total PBPs, phycocyanin (PC), allophycocyanin (APC), phycoerythrin (PE), and antioxidants (AOXs) capacity of Synechocystis salina (S. salina) strain LEGE 06155, based in factorial design resorting to Box-Behnken. The model predicted higher biomass productivities under a temperature of 25 °C, a pH of 7.5, and low NaCl concentrations (10 g·L−1). Maximum productivities in terms of bioactive compounds were attained at lower NaCl concentrations (10 g·L−1) (except for PE), with the best temperature and pH in terms of carotenoids and total and individual PBPs ranging from 23–25 °C to 7.5–9.5, respectively. PE was the only pigment for which the best productivity was reached at a lower temperature (15 °C) and pH (6.5) and a higher concentration of NaCl (≈25 g·L−1). AOX productivities, determined in both ethanolic and aqueous extracts, were positively influenced by lower temperatures (15–19 °C) and higher salinities (≈15–25 g·L−1). However, ethanolic AOXs were better recovered at a higher pH (pH ≈ 9.5), while aqueous AOXs were favored by a pH of 8. The model showed that biomass production can be enhanced by 175% (compared to non-optimized conditions), total carotenoids by 91%, PC by 13%, APC by 50%, PE by 130%, and total PBPs by 39%; for AOX productivities, only water extracts exhibited a (marginal) improvement of 1.4%. This study provided insightful information for the eventual upgrading of Synechocystis salina biomass in the biotechnological market. Full article
(This article belongs to the Special Issue Algae—a Step Forward in the Sustainability of Resources)
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24 pages, 2380 KiB  
Article
Factorial Optimization of Ultrasound-Assisted Extraction of Phycocyanin from Synechocystis salina: Towards a Biorefinery Approach
by Joana Assunção, Helena M. Amaro, Francisco Xavier Malcata and Ana Catarina Guedes
Life 2022, 12(9), 1389; https://doi.org/10.3390/life12091389 - 6 Sep 2022
Cited by 8 | Viewed by 3354
Abstract
PC is a bioactive and colorant compound widely sought in the food, nutraceutical and cosmetic industries, and one of the most important pigments produced by Synechocystis salina. However, the general extraction process is usually time-consuming and expensive, with low extraction yields—thus compromising [...] Read more.
PC is a bioactive and colorant compound widely sought in the food, nutraceutical and cosmetic industries, and one of the most important pigments produced by Synechocystis salina. However, the general extraction process is usually time-consuming and expensive, with low extraction yields—thus compromising a feasible and sustainable bioprocess. Hence, new extraction technologies (e.g., ultrasound assisted-extraction or UAE) emerged in the latest years may serve as a key step to make the overall bioprocess more competitive. Therefore, this study aimed at optimizing the yields of phycocyanin (PC) rich-extracts of S. salina by resorting to UAE; in attempts to explore this process in a more economically feasible way; valorization of the remaining cyanobacterial biomass, via extraction of other bioactive pigments and antioxidants, was tackled within a biorefinery perspective. A two-stage extraction (using ethanol and water) was thus performed (because it favors PC extraction); other bioactive pigments, including chlorophyll a (chl a), carotenoids, and other phycobiliproteins (PBPs), but also antioxidant (AOX) capacity and extraction yields were also evaluated for their optimum UAE yields. A factorial design based on Box–Behnken model was developed; and the influence of such extraction parameters as biomass to solvent ratio (B/S ratio = 1.5–8.5 mg·mL−1), duty cycle (DT = 40–100%), and percentage of amplitude (A = 40–100%) were evaluated. The model predicted higher PC yields with high B/S ratio = 6 mg·mL−1, lower DT = 80% and an A = 100%. Classical extraction was compared with UAE under the optimum conditions found; the latter improved PC yields by 12.5% and 47.8%, when compared to freeze-thawing extraction, and bead beater homogenization-based extraction, respectively. UAE successive extractions allowed to valorize other important bioactive compounds than PC, by reusing biomass, supporting a favorable contribution to the economic feasibility of the S. salina-based process towards a biorefinery approach. Full article
(This article belongs to the Special Issue Microalgae Metabolites)
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12 pages, 2332 KiB  
Article
Progesterone Metabolism by Human and Rat Hepatic and Intestinal Tissue
by Zoe Coombes, Katie Plant, Cristina Freire, Abdul W. Basit, Philip Butler, R. Steven Conlan and Deyarina Gonzalez
Pharmaceutics 2021, 13(10), 1707; https://doi.org/10.3390/pharmaceutics13101707 - 16 Oct 2021
Cited by 7 | Viewed by 4328
Abstract
Following oral administration, the bioavailability of progesterone is low and highly variable. As a result, no clinically relevant, natural progesterone oral formulation is available. After oral delivery, first-pass metabolism initially occurs in the intestines; however, very little information on progesterone metabolism in this [...] Read more.
Following oral administration, the bioavailability of progesterone is low and highly variable. As a result, no clinically relevant, natural progesterone oral formulation is available. After oral delivery, first-pass metabolism initially occurs in the intestines; however, very little information on progesterone metabolism in this organ currently exists. The aim of this study is to investigate the contributions of liver and intestine to progesterone clearance. In the presence of NADPH, a rapid clearance of progesterone was observed in human and rat liver samples (t1/2 2.7 and 2.72 min, respectively). The rate of progesterone depletion in intestine was statistically similar between rat and human (t1/2 197.6 min in rat and 157.2 min in human). However, in the absence of NADPH, progesterone was depleted at a significantly lower rate in rat intestine compared to human. The roles of aldo keto reductases (AKR), xanthine oxidase (XAO) and aldehyde oxidase (AOX) in progesterone metabolism were also investigated. The rate of progesterone depletion was found to be significantly reduced by AKR1C, 1D1 and 1B1 in human liver and by AKR1B1 in human intestine. The inhibition of AOX also caused a significant reduction in progesterone degradation in human liver, whereas no change was observed in the presence of an XAO inhibitor. Understanding the kinetics of intestinal as well as liver metabolism is important for the future development of progesterone oral formulations. This novel information can inform decisions on the development of targeted formulations and help predict dosage regimens. Full article
(This article belongs to the Special Issue Pre-clinical Pharmacology and Pharmacokinetics in Oral Drug Delivery)
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18 pages, 8785 KiB  
Article
Physio-Anatomical Study of Polyploid Watermelon Grafted by Different Methods
by Mohamed Omar Kaseb, Muhammad Jawad Umer, Eftekhar Mahmud, Muhammad Anees, Weinan Diao, Pingli Yuan, Hongju Zhu, Shengjie Zhao, Xuqiang Lu, Nan He, Eman El-remaly and Wenge Liu
Agronomy 2021, 11(5), 913; https://doi.org/10.3390/agronomy11050913 - 6 May 2021
Cited by 6 | Viewed by 3627
Abstract
Watermelon is one of the most desirable vegetable crops in the world. Recently, grafting is common in watermelons worldwide, but not all grafting methods are compatible with polyploids. In this study, diploid, triploid, and tetraploid from one watermelon variety, “Mi Mei”, were grafted [...] Read more.
Watermelon is one of the most desirable vegetable crops in the world. Recently, grafting is common in watermelons worldwide, but not all grafting methods are compatible with polyploids. In this study, diploid, triploid, and tetraploid from one watermelon variety, “Mi Mei”, were grafted on the “Xijiaqiangsheng” squash rootstock to study the effect of genome duplication on graft compatibility. Three grafting methods (splice, hole, and tongue) were used to determine graft compatibility. Significant differences in survival rates, hormones, antioxidants (AOX), sugars, and starch contents were observed between compatible/incompatible combinations. Compatible combinations with high survival rates showed high levels of hormones, AOX, carbohydrates, and low hydrogen peroxide H2O2 compared to incompatible plants. The hole grafting method was more efficient with diploid, while splice was efficient with a tetraploid, and both methods can be used for triploid. Compatibility is a combined effect of hormone, carbohydrate, and antioxidant activities. We predict that compatibility is a complex process and that further molecular studies must be performed to dig deep into this phenomenon. Full article
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15 pages, 1775 KiB  
Article
Improving Polyphenolic Compounds: Antioxidant Activity in Chickpea Sprouts through Elicitation with Hydrogen Peroxide
by Liliana León-López, Yudith Escobar-Zúñiga, Nancy Yareli Salazar-Salas, Saraid Mora Rochín, Edith Oliva Cuevas-Rodríguez, Cuauhtémoc Reyes-Moreno and Jorge Milán-Carrillo
Foods 2020, 9(12), 1791; https://doi.org/10.3390/foods9121791 - 2 Dec 2020
Cited by 42 | Viewed by 4726
Abstract
Elicitation appears to be a promising alternative to enhance the bioactive compound content and biological activities of legume sprouts. Multi-response optimization by response surface methodology (RSM) with desirability function (DF) was used to optimize the elicitor concentration (hydrogen peroxide (H2O2 [...] Read more.
Elicitation appears to be a promising alternative to enhance the bioactive compound content and biological activities of legume sprouts. Multi-response optimization by response surface methodology (RSM) with desirability function (DF) was used to optimize the elicitor concentration (hydrogen peroxide (H2O2)) and germination time in order to maximize total phenolic content (TPC), total flavonoids content (TFC), and antioxidant activity (AOX) of chickpea sprouts. Chemical, antinutritional, and nutraceutical properties of optimized chickpea sprouts (OCS) were also determined. The predicted regression models developed were efficiently fitted to the experimental data. The results of the desirability function revealed that optimum attributes in chickpea sprouts can be achieved by the application of 30 mM H2O2 and 72 h of germination time, with global desirability value D = 0.893. These OCS had higher (p < 0.05) TPC (7.4%), total iso-flavonoids (16.5%), AOX (14.8%), and lower phytic acid (16.1%) and saponins (21.8%) compared to H2O2 non-treated chickpea sprouts. Optimized germination conditions slightly modified the flavonoid profile in chickpea; eight iso-flavonoids were identified in OCS, including formononetin and biochanin A, which were identified as the major compounds. Results from this study support elicitation with H2O2 as an effective approach to improve phytochemical content and antioxidant activity in chickpea sprouts. Full article
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14 pages, 2505 KiB  
Article
Predicting Residual Adsorbable Organic Halides Concentrations in Industrial Wastewater Using Typical Wastewater Parameters
by Hannah Milh, Kwinten Van Eyck, Bert Bastiaens, Steven De Laet, Dirk Leysen, Deirdre Cabooter and Raf Dewil
Water 2020, 12(6), 1653; https://doi.org/10.3390/w12061653 - 9 Jun 2020
Cited by 5 | Viewed by 3527
Abstract
The aim of this study was to predict the residual adsorbable organic halides (AOX) concentration in an industrial wastewater using conventional, easy-to-measure wastewater parameters. In a pilot test unit, the wastewater was subjected to ozonation at various intensities, resulting in an AOX-removal and [...] Read more.
The aim of this study was to predict the residual adsorbable organic halides (AOX) concentration in an industrial wastewater using conventional, easy-to-measure wastewater parameters. In a pilot test unit, the wastewater was subjected to ozonation at various intensities, resulting in an AOX-removal and hence varying AOX concentrations. In first instance, the parameters used for modeling were selected using Pearson and Spearman correlations. Secondly, multiple linear regression (MLR) was used as a modeling tool to predict both the soluble and total AOX concentration in wastewater samples. To prevent overfitting, a 10-fold cross-validation was carried out. It was found that both the soluble and the total AOX concentration can be predicted using typical wastewater parameters. The measured parameters were pH, chloride concentration, Water-Soluble Organic Carbon concentration (WSOC), UV-VIS spectrum, turbidity, and Solids Removable by Filtration (SRF). Out of these parameters, the following parameters were found to be significant for prediction of the total AOX concentration: turbidity; SRF; UV-VIS absorbance at 200; 227, and 250 nm; and pH. UV-VIS absorbance at 200 and 227 nm and turbidity of the wastewater were found to contribute significantly to the final model. For the soluble AOX concentration, the significant parameters were turbidity; SRF; absorbance at 200, 227, and 250 nm; pH, and chloride concentration. Here, UV-VIS absorbance at 200 and 227 nm were found to contribute significantly to the final model. The obtained final models had an adjusted R2 of 0.921 and 0.916 for the total and soluble AOX, respectively. As a result of the obtained models, both AOX concentrations can be predicted using parameters that are easier to determine. This allows for a significant reduction in wastewater sampling and analysis time and offers the opportunity to optimize the ozone dosing in the wastewater treatment process in the future. Full article
(This article belongs to the Section Wastewater Treatment and Reuse)
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