Cytochrome B Research Articles

Disordered electron transfer: New forms of defective steroidogenesis and mitochondriopathy.

Most disorders of steroidogenesis, such as forms of congenital adrenal hyperplasia (CAH) are caused by mutations in genes encoding the steroidogenic enzymes and are often recognized clinically by cortisol deficiency, hyper- or hypo-androgenism, and/or altered mineralocorticoid function. Most steroidogenic enzymes are forms of cytochrome P450. Most P450s, including several steroidogenic enzymes, are microsomal, requiring electron donation by P450 oxidoreductase (POR); but several steroidogenic enzymes are mitochondrial P450s, requiring electron donation via ferredoxin reductase (FDXR) and ferredoxin (FDX). POR deficiency is a rare but well-described form of CAH characterized by impaired activity of 21-hydroxylase (P450c21, CYP21A2) and 17-hydroxylase/17,20-lyase (P450c17, CYP17A1); more severely affected individuals also have the Antley-Bixler skeletal malformation syndrome and disordered genital development in both sexes, and hence is easily recognized. The 17,20-lyase activity of P450c17 requires both POR and cytochrome b5 (b5), which promote electron transfer. Mutations of POR, b5, or P450c17 can cause selective 17,20-lyase deficiency. In addition to providing electrons to mitochondrial P450s, FDX and FDXR are required for the synthesis of iron-sulfur clusters, which are used by many enzymes. Recent work has identified FDXR mutations in patients with visual impairment, optic atrophy, neuropathic hearing loss and developmental delay, resembling the global neurologic disorders seen with mitochondrial diseases. Many of these patients have had life-threatening events or deadly infections, often without an apparent triggering event. Adrenal insufficiency has been predicted in such individuals but has only been documented recently. Neurologists, neonatologists and geneticists should seek endocrine assistance in evaluating and treating patients with mutations in FDXR.

Structural, Solvent, and Temperature Effects on Protein Junction Conductance.

Cytochrome b562 is a small redox-active heme protein that has served as an important model system for understanding biological electron transfer processes. Here, we present a comprehensive theoretical study of electron transport mechanisms in protein-metal junctions incorporating cytochrome b562 using a multi-scale computational approach. Employing molecular dynamics (MD) simulations, we generated junction geometries for both vacuum-dried and solvated conditions, with the protein covalently bound to gold contacts in various configurations. Coherent tunneling, described by the Landauer-Buttiker formalism within the density functional theory (DFT) framework, is compared to the incoherent hopping charge transport mechanism captured by the semi-classical Marcus theory. The tunneling was identified as the dominant mechanism explaining the experimental data measured on the cytochrome b562 junctions, exhibiting exponential yet very shallow distance dependence. While the structural orientations and protein contacts with the electrodes influence the junction conductance significantly, the solvation effects are relatively small, affecting the electronic properties mostly via the adsorption arrangement. On the other hand, the considerable temperature dependence of the conductance was found strong only for hopping, while the tunneling current magnitudes remain practically unaffected and are a good indicator of the coherent mechanism in this case.

OXPHOS mediators in acute myeloid leukemia patients: Prognostic biomarkers and therapeutic targets for personalized medicine

BackgroundDespite significant advances in comprehending its tumorigenic role, the prognostic and therapeutic potential of targeting oxidative phosphorylation (OXPHOS) in acute myeloid leukemia (AML) remain obscure.MethodsThe prognostic value of ~ 200 mitochondrial/OXPHOS genes as candidate biomarkers was examined in AML patients over ~ 10 years follow-up using Kaplan–Meier and Cox regression analyses. Furthermore, the transcript levels of the assessed markers were inspected in healthy bone marrow tissues and the dependencies of AML cells on the assessed genes were examined.ResultsElevated levels of NADH:ubiquinone oxidoreductase subunit A6 (NDUFA6), succinate dehydrogenase complex flavoprotein subunit A (SDHA), solute carrier family 25 member 12 (SLC25A12), electron transfer flavoprotein subunit beta (ETFB), carnitine palmitoyltransferase 1A (CPT1A) and glutathione peroxidase 4 (GPX4) were associated with poor overall survival of AML patients. SLC25A12, ETFB and CPT1A were overexpressed in AML compared to healthy tissues. Cytochrome B5 type A (CYB5A)high, SLC25A12high and GPX4high AML patients displayed higher levels of circulating and engrafted blasts compared to low-expressing cohorts. NPM1 and SRSF2 mutations were frequent in SDHAlow and CPT1Alow AML patients respectively. FLT3-ITD, NPM1 and IDH1 mutations were prevalent in CPT1Ahigh AML patients. FLT3-ITD AMLs were more dependent on OXPHOS.ConclusionsThis study identifies NDUFA6 and SDHA as novel companion prognostic biomarkers which might present a rational strategy for personalized therapy of AML patients.Graphical

Benzylurea Protects hPDLFs Against LPS-Induced Mitochondrial Dysfunction Through MTCH2.

The aim of this study is to explore the mechanism of benzylurea in the inflammatory injury of human periodontal ligament fibroblasts (hPDLFs). An inflammation model of hPDLFs was established using LPS. Nuclear transport of nuclear transcription factor-κB (NF-κB), secretion of cytokines, and the morphology and distribution of F-actin were determined. Mitochondrial function was assessed by measuring mitochondrial membrane potential (MMP), mitochondrial permeability transition pore (mPTP), and reactive oxygen species (ROS) levels. The expression of mitochondrial carrier homolog 2 (MTCH2) and Cytochrome b5 type B (CYB5B) was detected. Benzylurea alleviated the effects of lipopolysaccharide (LPS) on the proliferation and apoptosis of hPDLFs. It reduced the release of inflammatory cytokines and inhibited NF-κB nuclear translocation. Benzylurea improved mitochondrial function by regulating MMP and preventing excessive mPTP opening. Furthermore, LPS elevated the expression of MTCH2 and reduced the expression of CYB5B in hPDLFs. However, these effects can be inhibited by benzylurea. The altered expression of MTCH2 directly affected CYB5B expression, the release of inflammatory cytokines, and the activation of nuclear translocation of NF-κB. CYB5B may act as an effector of MTCH2, with benzylurea enhancing mitochondrial function and protecting hPDLFs from LPS-induced injury through MTCH2.

The role of loss of cytochrome b5 reductase 3 (CYB5R3) in high-grade serous ovarian cancer

The role of loss of cytochrome b5 reductase 3 (CYB5R3) in high-grade serous ovarian cancer

Cytochrome b5 reductase 3 overexpression and dietary nicotinamide riboside supplementation promote distinctive mitochondrial alterations in distal convoluted tubules of mouse kidneys during aging.

The kidney undergoes structural and physiological changes with age, predominantly studied in glomeruli and proximal tubules. However, limited knowledge is available about the impact of aging and anti-aging interventions on distal tubules. In this study, we investigated the effects of cytochrome b5 reductase 3 (CYB5R3) overexpression and/or dietary nicotinamide riboside (NR) supplementation on distal tubule mitochondria. Initially, transcriptomic data were analyzed to evaluate key genes related with distal tubules, CYB5R3, and NAD+ metabolism, showing significant differences between males and females in adult and old mice. Subsequently, our emphasis focused on assessing how these interventions, that have demonstrated the anti-aging potential, influenced structural parameters of distal tubule mitochondria, such as morphology and mass, as well as abundance, distance, and length of mitochondria-endoplasmic reticulum contact sites, employing an electron microscopy approach. Our findings indicate that both interventions have differential effects depending on the age and sex of the mice. Aging resulted in an increase in mitochondrial size and a decrease in mitochondrial abundance in males, while a reduction in abundance, size, and mitochondrial mass was observed in old females when compared with their adult counterparts. Combining both the interventions, CYB5R3 overexpression and dietary NR supplementation mitigated age-related changes; however, these effects were mainly accounted by NR in males and by transgenesis in females. In conclusion, the influence of CYB5R3 overexpression and dietary NR supplementation on distal tubule mitochondria depends on sex, genotype, and diet. This underscores the importance of incorporating these variables in subsequent studies to comprehensively address the multifaceted aspects of aging.

Cytochromes b5 Occurrence in Viruses Belonging to the Order Megavirales.

Cytochrome b5 is a small electron transport protein that is found in animals, plants, fungi and photosynthetic proteobacteria where it plays key metabolic roles in energy production, lipid and sterol biosynthesis and cytochrome P450 biochemistry. Previously it was shown that a gene encoding a soluble and functional cytochrome b5 protein was encoded in the large double stranded DNA virus OtV2 that infects the unicellular marine green alga Ostreococcus tauri, the smallest free-living eukaryote described to-date. This single gene represented a unique finding in the virosphere. We now report that genes for soluble and membrane-bound cytochromes b5 also occur in giant viruses in the proposed order Megavirales, particularly the AT-rich Mimiviridae and Tupanviruses. Conversely, other members of the Megavirales taxa such as the GC-rich Pandoraviridae have not been found to encode cytochrome b5 as yet. Megaviruses encoding cytochrome b5 have been isolated from the deep ocean, from freshwater and terrestrial sources, as well as from human patients. Giant virus cytochrome b5 proteins share high sequence identity with one another (45-95% depending on group) but no more than 25% identity with the cytochrome b5 gene product we identified in Acanthamoeba castellanii, an amoeba host for many giant viruses. Thus, the origin of the unique cytochrome b5 genes in giant viruses remains unknown. Examination of viral cytochrome b5 primary amino acid sequences revealed that some have either a N- or C-terminal transmembrane anchor, whilst others lack a membrane anchor and are thus predicted to be soluble proteins. This cytochrome b5 topography suggests adapted biochemical functions in those viruses. Our findings raise questions regarding the evolution and diversity of cytochrome b5 proteins in nature, adding to questions about the origin of viral haemoproteins in general.

High-fidelity PAMless base editing of hematopoietic stem cells to treat chronic granulomatous disease.

X-linked chronic granulomatous disease (X-CGD) is an inborn error of immunity (IEI) resulting from genetic mutations in the cytochrome b-245 beta chain (CYBB) gene. The applicability of base editors (BEs) to correct mutations that cause X-CGD is constrained by the requirement of Cas enzymes to recognize specific protospacer adjacent motifs (PAMs). Our recently engineered PAMless Cas enzyme, SpRY, can overcome the PAM limitation. However, the efficiency, specificity, and applicability of SpRY-based BEs to correct mutations in human hematopoietic stem and progenitor cells (HSPCs) have not been thoroughly examined. Here, we demonstrated that the adenine BE ABE8e-SpRY can access a range of target sites in HSPCs to correct mutations causative of X-CGD. For the prototypical X-CGD mutation CYBB c.676C>T, ABE8e-SpRY achieved up to 70% correction, reaching efficiencies greater than three-and-one-half times higher than previous CRISPR nuclease and donor template approaches. We profiled potential off-target DNA edits, transcriptome-wide RNA edits, and chromosomal perturbations in base-edited HSPCs, which together revealed minimal off-target or bystander edits. Edited alleles persisted after transplantation of the base-edited HSPCs into immunodeficient mice. Together, these investigational new drug-enabling studies demonstrated efficient and precise correction of an X-CGD mutation with PAMless BEs, supporting a first-in-human clinical trial (NCT06325709) and providing a potential blueprint for treatment of other IEI mutations.

A Case for Co-oximetry: Methemoglobinemia secondary to a Rare Hemoglobin Variant

Abstract Introduction/Objective The presence of dyshemoglobins and some inherited hemoglobin (Hb) variants can cause over or underestimation of oxygen saturation (O2sat) when using a pulse oximeter (ox). These noninvasive medical devices rely on two wavelengths, a pulsing arterial bed, and light absorption properties of Hb to measure the difference between deoxy- and oxy-Hb. In contrast, a co-oximeter (co-ox) requires arterial blood. By using at least four wavelengths, co-ox measures the functional and fractional O2sat to detect all forms of Hb, including those that do not bind oxygen (O2), such as methemoglobin (metHb). Methemoglobinemia may be congenital or acquired, resulting from exposure to certain toxins, metabolic disorders, enzymatic deficiencies such as cytochrome b5 reductase deficiency, or hemoglobinopathies. Methods/Case Report A healthy, adolescent male undergoing a sports physical at his pediatrician’s office was hypoxic by pulse ox and sent to the emergency department (ED) for evaluation. On exam, he had cold, blue tinged fingertips and lips but was otherwise asymptomatic. His O2sat was 88-90% on room air with minimal improvement with 6L of supplemental O2. Co-ox revealed a metHb level > 20%. The father also mentioned that the mother had frequent ED visits for hypoxia. Capillary Hb electrophoresis showed peaks in the HbA, HbF, and HbA2 zones of 78.3%, 17.9%, and 3.6%, respectively. All CBC parameters were within the reference intervals. The large peak in the HbF zone would suggest hereditary persistence of fetal hemoglobin (HPFH); however, the clinical picture was not consistent. Further reference laboratory investigation determined that the patient was heterozygous for Hb Tübingen (HbTüb), a beta globin chain variant resulting from a point mutation at position 106. By mass spectrometry, the variant quantified as 38% of the total hemoglobin, indicating underestimation by electrophoretic techniques. Results (if a Case Study enter NA) NA Conclusion This case presents an essentially asymptomatic patient with hypoxia and elevated methemoglobin levels. Electrophoretic hemoglobinopathy and CBC workup were clinically inconsistent with HPFH and the presence of an aberrant hemoglobin migrating in the HbF must be considered in the differential diagnosis. The manifestation of HbTüb as methemoglobinemia in this context adds complexity to the diagnostic puzzle. Further laboratory exploration into the underlying mechanisms driving this unique presentation is crucial for a comprehensive understanding and tailored management approach.

Functional Analysis of Cytochrome b5 in Regulating Anthocyanin Biosynthesis in Malus domestica

Cytochrome b5 (CB5), a small heme-binding protein, plays an important role in plant biotic and abiotic stress. Anthocyanin is a critical determinant for fruit coloration, however, whether CB5 is involved in regulating anthocyanin biosynthesis has not yet been investigated in apple fruit (Malus domestica). In this study, we determined that MdCYB5, an apple CB5 gene, was a positive regulator for anthocyanin biosynthesis in apple fruit. We first found that MdCYB5 showed a high sequence and structural similarity with Arabidopsis cytochrome b5 isoform E (CB5E) at the protein level. Quantitative reverse transcription PCR (qRT-PCR) analysis showed that MdCYB5 responds to light signals. Subcellular localization showed that MdCYB5 is localized to the cytoplasmin inthe epidermal cells of Nicotiana benthamiana leaves. Further investigation revealed that overexpressing MdCYB5 promoted anthocyanin biosynthesis in both apple calli and tissue-cultured apple seedlings. Furthermore, results of transient expression assay showed that overexpressing MdCYB5 promoted anthocyanin accumulation and fruit coloration in apple fruit. Taken together, this study suggests that MdCYB5 has a positive regulatory effect on anthocyanin biosynthesis in apple fruit.

Bone and periosteum protein analysis via tandem mass tag quantitative proteomics in pediatric patients with osteomyelitis.

Bone healing is crucial in managing osteomyelitis after fracture fixation. Understanding the mechanism of extensive callus formation in pediatric osteomyelitis is highly important. This study aims to analyze bone and periosteum samples from pediatric patients to elucidate the essential processes involved in callus formation during osteomyelitis. The study included eight patients from our hospital: four with positive microbial culture who underwent osteomyelitis debridement and four who had osteotomy surgery as contral. We used tandem mass tag quantitative proteomics to investigate proteomic changes in bone and periosteum tissues obtained from these patients. Differential expression proteins were analyzed for their pathways through Gene Ontology (GO) annotation, GO enrichment analysis, Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment analysis, and protein-protein interaction networks. A total of 4737 proteins were successfully identified. About 2224 differentially expressed proteins were detected in the bone tissues group and periosteum tissues group. Among the differentially expressed proteins, 10 protein genes in the bone group were associated with inflammation and osteogenesis, while in the periosteum group were nine. Cytochrome b-245, beta polypeptide (CYBB), nicotinamide phosphoribosyltransferase (NAMPT), tissue inhibitor of metalloproteinases 1 (TIMP-1), Raf-1 proto-oncogene, serine/threonine kinase (RAF-1), RELA proto-oncogene, NF-KB subunit (RELA), and sphingomyelin synthase 2 (SGMS2) may play an important role in callus formation in patients with osteomyelitis. This study provides novel clues for understanding callus formation in pediatric patients with osteomyelitis.

Revealing the Genetic Differentiation of Rattus norvegicus (Berkenhout 1769) Populations by Analyzing Two Mitochondrial Markers

Rattus norvegicus (Brown rat) has a great importance for public health and economy because it lives in close association with human populations. However, molecular systematic studies on global populations of R. norvegicus are very few. In this study, sequences obtained from Europe, Asia, Africa, and America regions were analyzed using mitochondrial Cytochrome-b and Cytochrome oxidase-I gene regions and genetic differentiation levels between these populations were revealed. Accordingly, samples belonging to the studied populations did not split in Bayesian Inference trees and Median-joining networks; these samples also formed common haplotypes, and mean genetic distance and fixation index values were generally low. The results of the study showed that gene flow between these populations may be continuing due to the transportation activity by humans.

Phylogeography of the Sinica Group of Macaques in the Himalayas: Taxonomic and Evolutionary Implications.

Owing to the taxonomic incongruence between the morphological features and genetic relationships of the sinica group of macaques (genus Macaca), the taxonomy of this macaque group has remained inconclusive. We aimed to resolve the taxonomic quandary and improve our understanding of the historical biogeography of the group by including macaque DNA samples from previously unsampled areas in the Himalayas. We sequenced and analyzed three mitochondrial DNA loci [cytochrome b (CYTB), cytochrome oxidase subunit 1 (COI) and D-loop; 2898 bp] for sequence polymorphism, phylogenetics, species delimitation, and ancestral area reconstruction. We confirmed the occurrence of Arunachal macaque (Macaca munzala) on the southern slopes of the Eastern Himalayas in the Xizang Zizhiqu (Tibet Autonomous Region) of China. The results revealed that the sinica group of macaques is a parapatric species group composed of seven distinct species. Phylogenetic and species delimitation analyses revealed that the two previously considered subspecies of Assamese macaques (the eastern subspecies M. assamensis assamensis and the western subspecies M. a. pelops) are two distinct species. The eastern Assamese macaque is a sister species to the Tibetan macaque, whereas the western Assamese macaque and Arunachal macaque are the closest genetic sister species. The sinica group of macaques underwent five vicariance and seven dispersal radiations in the past, which mainly coincided with the Quaternary climatic oscillations between the late Pliocene and the late Pleistocene. By integrating our phylogenetic and ancestral area reconstruction results with findings from previous paleontological and molecular studies, we propose a robust hypothesis about the phylogeography of the sinica group of macaques.

RESISTANCE TO PHYTOPHTHORA1 promotes cytochrome b559 formation during early photosystem II biogenesis in Arabidopsis.

As an essential intrinsic component of photosystem II (PSII) in all oxygenic photosynthetic organisms, heme-bridged heterodimer cytochrome b559 (Cyt b559) plays critical roles in the protection and assembly of PSII. However, the underlying mechanisms of Cyt b559 assembly are largely unclear. Here, we characterized the Arabidopsis (Arabidopsis thaliana) rph1 (resistance to Phytophthora1) mutant, which was previously shown to be susceptible to the oomycete pathogen Phytophthora brassicae. Loss of RPH1 leads to a drastic reduction in PSII accumulation, which can be primarily attributed to the defective formation of Cyt b559. Spectroscopic analyses showed that the heme level in PSII supercomplexes isolated from rph1 is significantly reduced, suggesting that RPH1 facilitates proper heme assembly in Cyt b559. Due to the loss of RPH1-mediated processes, a covalently bound PsbE-PsbF heterodimer is formed during the biogenesis of PSII. In addition, rph1 is highly photosensitive and accumulates elevated levels of reactive oxygen species under photoinhibitory-light conditions. RPH1 is a conserved intrinsic thylakoid protein present in green algae and terrestrial plants, but absent in Synechocystis, and it directly interacts with the subunits of Cyt b559. Thus, our data demonstrate that RPH1 represents a chloroplast acquisition specifically promoting the efficient assembly of Cyt b559, probably by mediating proper heme insertion into the apo-Cyt b559 during the initial phase of PSII biogenesis.

Exploration of key ferroptosis-related genes as therapeutic targets for sepsis based on bioinformatics and the depiction of their immune profiles characterization

To explore the characteristics of key ferroptosis-related genes as therapeutic targets for sepsis based on bioinformatics analysis, and describe their immune characteristics. The transcriptome datasets GSE57065, GSE9960, GSE28750, and GSE137340 were downloaded from the Gene Expression Omnibus (GEO) database, immune-related gene (IRG) were obtained from ImmPort and InnateDB databases, and ferroptosis-related gene (FRG) were downloaded from the FerrDb database. The datasets GSE57065, GSE9960, and GSE28750 were integrated into an analysis dataset by the surrogate variable analysis (SVA) package and analyzed this analysis dataset by using the "limma" package to obtain differentially expressed gene (DEG), then the intersection set of DEG, FRG, and IRG were considered as ferroptosis and immune-related DEG (FImDEG). Gene ontology (GO) functional annotation and Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment analyses were performed using "ClusterProfiler" to understand the biological function of FImDEG. The key genes were screened by protein-protein interaction (PPI) network, least absolute shrinkage and selection operator (LASSO) regression algorithms, and support vector machine (SVM) analyses, and Logistic regression model was built based on above key genes. Receiver operator characteristics curve (ROC curve) was plotted to evaluate the diagnostic efficacy of the key genes alone or combinative. The degree of infiltration of 22 immune cells was assessed using the "CIBERSORT" package, and the correlation between the expressions of key genes and infiltration degree of immune cells was analyzed. Dataset GSE137340 was used to verify these key genes. A dataset consisting of 146 sepsis samples and 61 healthy control samples was obtained by processing the database and removing batch effect. A total of 4 537 DEG were obtained, including 2 066 up-regulated genes and 2 471 down-regulated genes. 2 519 IRG and 855 FRG were obtained from the relevant database. Using the intersection of DEG, IRG and FRG, 34 FImDEG were obtained, including 20 up-regulated genes and 14 down-regulated genes. GO functional annotation showed that the biological functions of 34 FImDEG were mainly inhibition of transferase activity, regulation of DNA-binding transcription factor activity and cell response to stimulation. In terms of molecular function, it was mainly related to RNA polymerase II-specific DNA-binding transcription factor binding and various protein ligase binding. Changes in cell composition occurred mainly in promyelocytic leukemia protein and chromatin silencing complexes. Enrichment analysis of KEGG pathway showed that the major pathways involved in 34 FImDEG included cell aging, expression of programmed death-ligand 1 (PD-L1) and programmed death-1 (PD-1) checkpoint pathways in cancer, interleukin-17 (IL-17) signaling pathway, lipid and atherosclerosis, and NOD-like receptor signaling pathway. Four key genes, including cytochrome b-245 β chain (CYBB), mitogen-activated protein kinase 14 (MAPK14), prostaglandin-endoperoxide synthase 2 (PTGS2) and V-relreticuloendotheliosis viral oncogene homology A (RELA), were screened through PPI network and LASSO and SVM machine learning. ROC curve analysis showed that the area under ROC curve (AUC) of the four key genes for diagnosing sepsis was all greater than 0.65, and the AUC of MAPK14 was 0.911. Logistic regression model was constructed based on four key genes, and the AUC was 0.956. Immunoinfiltration analysis showed that compared with healthy control samples, the infiltration degree of neutrophils and macrophages M0 was significantly increased in sepsis samples, while the infiltration degree of resting natural killer cell (NK cell), naive CD4+ T cell and CD8+ T cell was significantly lowered. Correlation analysis showed that the positive correlation between MAPK14 expression and the infiltration degree of neutrophils was the highest. Validation results in the GSE137340 dataset showed that compared with healthy control samples, the expressions of CYBB and MAPK14 in sepsis samples were significantly up-regulated, however, the expressions of PTGS2 and RELA were significantly down-regulated, similar to the expression trend in the above analysis dataset. Four key genes, including CYBB, MAPK14, PTGS2, and RELA, in the development of sepsis were identified through bioinformatics analysis, which play an important role in the immune process, and MAPK14 may be an important target for immune intervention.

Membrane protein provision controls prothylakoid biogenesis in tobacco etioplasts.

The cytochrome b559 heterodimer is a conserved component of photosystem II whose physiological role in photosynthetic electron transfer is enigmatic. A particularly puzzling aspect of cytochrome b559 has been its presence in etiolated seedlings, where photosystem II is absent. Whether or not the cytochrome has a specific function in etioplasts is unknown. Here, we have attempted to address the function of cytochrome b559 by generating transplastomic tobacco (Nicotiana tabacum) plants that overexpress psbE and psbF, the plastid genes encoding the two cytochrome b559 apoproteins. We show that strong overaccumulation of the PsbE apoprotein can be achieved in etioplasts by suitable manipulations of the promoter and the translation signals, while the cytochrome b559 level is only moderately elevated. The surplus PsbE protein causes striking ultrastructural alterations in etioplasts; most notably, it causes a condensed prolamellar body and a massive proliferation of prothylakoids, with multiple membrane layers coiled into spiral-like structures. Analysis of plastid lipids revealed that increased PsbE biosynthesis strongly stimulated plastid lipid biosynthesis, suggesting that membrane protein abundance controls prothylakoid membrane biogenesis. Our data provide evidence for a structural role of PsbE in prolamellar body formation and prothylakoid biogenesis, and indicate that thylakoid membrane protein abundance regulates lipid biosynthesis in etioplasts.

Cell differentiation controls iron assimilation in a choanoflagellate.

Marine microeukaryotes have evolved diverse cellular features that link their life histories to surrounding environments. How those dynamic life histories intersect with the ecological functions of microeukaryotes remains a frontier to understand their roles in essential biogeochemical cycles1,2. Choanoflagellates, phagotrophs that cycle nutrients through filter feeding, provide models to explore this intersection, for many choanoflagellate species transition between life history stages by differentiating into distinct cell types3-6. Here we report that cell differentiation in the marine choanoflagellate Salpingoeca rosetta endows one of its cell types with the ability to utilize insoluble ferric colloids for improved growth through the expression of a cytochrome b561 iron reductase (cytb561a). This gene is an ortholog of the mammalian duodenal cytochrome b561 (DCYTB) that reduces ferric cations prior to their uptake in gut epithelia7 and is part of an iron utilization toolkit that choanoflagellates and their closest living relatives, the animals, inherited from a last common eukaryotic ancestor. In a database of oceanic metagenomes8,9, the abundance of cytb561a transcripts from choanoflagellates positively correlates with upwellings, which are a major source of ferric colloids in marine environments10. As this predominant form of iron11,12 is largely inaccessible to cell-walled microbes13,14, choanoflagellates and other phagotrophic eukaryotes may serve critical ecological roles by first acquiring ferric colloids through phagocytosis and then cycling this essential nutrient through iron utilization pathways13-15. These findings provide insight into the ecological roles choanoflagellates perform and inform reconstructions of early animal evolution where functionally distinct cell types became an integrated whole at the origin of animal multicellularity16-22.

Transcriptome sequencing-based analysis of primary vein development in Betula pendula ‘Dalecarlica’

Keymessage The study revealed the major biological processes occurred at three developmental stages and identified candidate genes involved in primary vein development of birch plants.Vascular tissues usually mirror the surrounding leaf shape and its development plays a fundamental role in plant performance. However, the information of vascular development in birch trees, especially primary vein development, remains unclear. Therefore, we conducted the anatomical observation on primary veins from leaves at different development stages in Betula pendula ‘Dalecarlica’. With the development of primary vein, dynamic changes in mechanical tissue thickness and primary vein diameter were consistent with each other, and the sum of phloem, xylem and cambium thickness was significantly varied. Transcriptome analysis indicated that primary vein development could be divided into three stages, namely Stage I, II and III, which were in aggreement with anatomical observation. Expression of marker genes associated with vascular tissues revealed that pro-vasculature development occurred at Stage I and II, and phloem development occurred at Stage III. GO enrichment analysis of differentially expressed genes (DEGs) showed that shared DEGs at Stage II were mainly engaged in cell division and cell cycle, and shared DEGs at Stage III were mainly engaged in phosphorylation. Decreased cell division and cell cycle as well as activation of lignin biosynthesis might contribute to primary vein development. Combining phenotypic traits, we performed weighted gene co-expression network analysis and identified a cytochrome P450 84A (CYP84A) family gene (BpF5H1). Based on analyses of gene families, expression patterns and yeast-two hybrid assay results, we proposed a potential electron transfer pathway involving BpF5H1 and three cytochrome b5 proteins during primary vein development in B. pendula ‘Dalecarlica’. These results could shed some light on which biological processes occurred during primary vein formation and provide some valuable clues for vascular morphogenesis in woody plants.

Molecular species identification from seized dried genital organs: a case study of suspected Bengal monitor lizard (Varanus bengalensis)

The bifurcated hemipenes of any of the four species of Monitor lizards found in India is illegally traded under the name ‘Hatha Jodi’ (a plant root from Martynia annua). A rare plant root is misrepresented as a powerful charm capable of bringing property and good fortune to its possessor. As a result, there is a suspected large-scale poaching of monitors in India to fuel the trade of ‘Hatha Jodi’. With this regard, here we report a case where the Tamil Nadu Forest Department officers seized dried genital organs. We extracted DNA from the seized dried genital organs and amplified a partial fragment of the mitochondrial cytochrome-b gene (cytb). Then, generated DNA sequences were analyzed and confirmed that the dried genital organs were consistent with the Bengal monitor lizard with 99% similarity. In forensic case analysis, dried and processed samples are not preferred for DNA-based analysis. This is due to the low yield of DNA and increased PCR inhibitors, which lead to low success in such experiments. However, the present study demonstrated species identification through DNA analysis from seized dried genital organs and supported law enforcement in successfully prosecuting the case.

Visual analysis on ferroptosis and its cross-talk to coronavirus disease 2019 (COVID-19)

BackgroundFerroptosis is a new type of programmed cell death. Although ferroptosis has been studied in various aspects, there has been no visual analysis of ferroptosis in coronavirus disease 2019 (COVID-19) to date. It is still a global health concern of the COVID-19 pandemic worldwide, three years after its outbreak. Yet the emergence of the mutant strain Omicron has caused a fourth wave of infections in many countries. The pathogenesis of COVID-19 is still undergoing extensive exploration, which holds paramount importance in mitigating future epidemics. MethodsFor this study, CiteSpace 6.2 R4 software was used for bibliometric and visual atlas analysis of ferroptosis-related research, and the Genecards database was used to mine ferroptosis and COVID-19-related genes. ResultsWe found increasing studies about ferroptosis. China and the United States have demonstrated robust scientific innovation over recent years, with extensive collaboration between their institutions and authors. Ferroptosis and COVID-19 were seen to have 13 shared genes, which may be new targets for the treatment of COVID-19 in the future. Most of the shared genes are enriched in tumor necrosis factor (TNF) pathways. The majority of those genes are up-regulated under the cellular response to oxidative stress. Genes including Tumour necrosis factor (TNF), RELA proto-oncogene (RELA), Activating transcription factor 4 (ATF4), Cytochrome b-245 beta chain (CYBB), Jun proto-oncogene (JUN), Mitogen-activated protein kinase 1 (MAPK1) and Heme oxygenase 1 (HMOX1), maybe a breakthrough for ferroptosis and COVID‐19. Whilst previous research has shown there to be a relationship between ferroptosis and COVID‐19, the specific role of ferroptosis remained unclear. Our study aimed to analyze the research status of ferroptosis and its relationship with COVID-19, to provide a useful reference for further prevention and treatment of COVID-19. Overall, uncovering the role of ferroptosis in SARS-CoV-2 infection is important for the development of new treatment strategies for COVID-19.